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Few studies have examined brief transdiagnostic groups. The Take Control Course (TCC) was developed for patients with mild to moderate common mental health problems. We examined whether TCC is non-inferior to individual low-intensity cognitive behaviour therapy (CBT) in a single-blind individually randomised parallel non-inferiority trial. The primary outcomes were depression (PHQ9) and anxiety (GAD7) at 6-month follow-up (primary outcome point) and 12-month follow-up. The non-inferiority margin that we set, based on previous trials, corresponds to approximately 3 points on the PHQ9 and approximately 2.5 points on the GAD7. Intention-to-treat (ITT) and per-protocol (PP) analyses of 6-month data of 156 randomised patients indicated that TCC was non-inferior to individual low-intensity CBT on anxiety (ITT Coefficient = 0.24; 95% CI: -1.45 to 1.92; d = 0.04; p = .79), and depression (ITT Coefficient = 0.82; 95% CI: -1.06 to 2.69; d = 0.14; p = .39) outcomes, and functioning (ITT Coefficient = 0.69; 95% CI: -2.56 to 3.94; d = 0.08; p = .68). The findings at 12 months were inconclusive and require further testing. This randomised trial provides preliminary support that TCC is not less effective than short-term individual CBT within Improving Access to Psychological Therapies (IAPT) services.

Background: The prevalence of child and adolescent mental health issues are rising faster than the number of services available, leading to a shortfall. Mental health chatbots are a highly scalable way to address this gap. Manage Your Life Online (‘MYLO’) is an artificially intelligent chatbot that emulates Method of Levels Therapy (MOL). MOL is a style of therapy that uses curious questioning to support sustained awareness and exploration of current problems. Objective: To assess the feasibility and acceptability of a co-designed interface for MYLO in young people aged 16-24 with mental health problems. Methods: An iterative co-design phase occurred over 4 months, in which feedback was elicited from a group of young people (N = 7) with lived experience of mental health issues. This resulted in the development of a progressive web application version of MYLO that could be used on mobile phones. We then conducted a case-series to assess feasibility and acceptability in 13 young people over 2 weeks. During this time the participants tested MYLO and completed surveys including clinical outcomes and acceptability measures. We then conducted focus groups and interviews, and used thematic analysis, to obtain feedback on MYLO and identify recommendations for further improvements.Results: Most participants were positive about their experience of using MYLO and would recommend MYLO to others. Participants enjoyed the simplicity of the interface, found it easy to use, and rated it as acceptable on a system usability scale. Inspection of the usage data found evidence that MYLO can learn and adapt its questioning in response to user inputs. We found a large effect size for the decrease in participants’ problem-related distress and a medium effect size in the increase in their self-reported tendency to resolve goal conflicts (the proposed mechanism of change) over the testing phase. Some patients, also, experienced reliable change in their clinical outcome measures over the two-weeks.Conclusions: We have established the feasibility and acceptability of MYLO. Initial outcomes suggest MYLO has the potential to support young people’s mental health and help them to resolve their own problems. We aim to establish whether the use of MYLO leads to meaningful reductions in participants’ symptoms of depression and anxiety, and whether these are maintained over time, by conducting a randomised controlled evaluation trial.

Background: Sleep disturbance is considered a transdiagnostic process due to high comorbidity with mental health difficulties. In particular, sleep disturbances are a feature of mood disorders. To advance transdiagnostic psychological interventions targeting sleep, the Positive and Negative Sleep Appraisal Measure (PANSAM) was developed. The PANSAM is a theory-driven measure based on an Integrative Cognitive Sleep Model and proposes that positive and negative sleep appraisals for excessively long and short sleep durations play a key role in the development of insomnia, hypersomnia, and reduced need for sleep. This study evaluated clinical validity of this new measure. Methods: Participants were those who met bipolar at risk criteria and bipolar diagnoses (bipolar spectrum group) (N = 22), major depressive disorder (unipolar depression group) (N = 18), and a nonclinical group (N = 22). To compare against previous insomnia and bipolar disorder relevant research, administered measures included the Dysfunctional Beliefs and Attitudes about Sleep Scale (DBAS) and the Hypomanic and Positive Predictions Inventory (HAPPI). Results: Analysis of variance (ANOVA) tests revealed that the clinical groups scored significantly higher on the PANSAM. The same was shown for the DBAS and HAPPI. Post hoc analyses showed that the PANSAM scale and subscales had significant correlations with all clinical measures. Effect sizes are reported due to sample size limitations. Conclusion: This study has initially validated the PANSAM with clinical populations and highlighted its applicability to a transdiagnostic approach.

There are many different approaches to psychotherapy. Research indicates comparable effectiveness of various therapies, despite having different theoretical assumptions and using different therapeutic methods. In recent years, many researchers have attempted to understand such results by investigating specific and common factors in psychotherapy. It has been suggested that further developments in the field should aim to investigate factors underlying mental health problems and the principles informing the process of change in psychotherapy. In the current article, we will present perceptual control theory as a scientifically grounded approach that integrates theory and practice. Transdiagnostic principles explain the sources of emotional distress and the process of psychological change in psychotherapy. The main aim of the article is to introduce method of levels therapy, which has been created as a direct application of perceptual control theory principles. Description of the process of therapy is accompanied by clinical examples.

The quality of parent-child relationships during adolescence has the potential to impact adolescents’ mental health. The current study explored how seven young people (11-15 years old) might experience a two-component intervention (Method of Levels therapy-MOL and a parent-child activity). Young people chose how often to engage in the intervention during a four-month period. On completion, six participants were interviewed. Interviews were audio recorded, transcribed verbatim and analysed using thematic analysis. Three main themes were generated: 1) Shared Goals and MOL (subthemes relevant to both Shared Goals and MOL); 2) Shared Goals (elements relevant to the Shared Goals activity only); and 3) MOL- (one subtheme representative of MOL only). The most helpful aspect of the two-component intervention both for young people and their parents was the opportunity to talk. The intervention facilitated helpful conversations that increased participants awareness and broadened their perspective on the topics discussed. This process helped participants find solutions to their problems. Young people and parents reported that through the use of the Shared Goals activity their communication and relationships improved. Young people stated that MOL offered them the opportunity to figure things out for themselves.

Funder: University of Cambridge, Sensorimotor delays dictate that humans act on outdated perceptual information. As a result, continuous manual tracking of an unpredictable target incurs significant response delays. However, no such delays are observed for repeating targets such as the sinusoids. Findings of this kind have led researchers to claim that the nervous system constructs predictive, probabilistic models of the world. However, a more parsimonious explanation is that visual perception of a moving target position is systematically biased by its velocity. The resultant extrapolated position could be compared with the cursor position and the difference canceled by negative feedback control, compensating sensorimotor delays. The current study tested whether a position extrapolation model fit human tracking of sinusoid (predictable) and pseudorandom (less predictable) targets better than the non-biased position control model, Twenty-eight participants tracked these targets and the two computational models were fit to the data at 60 fixed loop delay values (simulating sensorimotor delays). We observed that pseudorandom targets were tracked with a significantly greater phase delay than sinusoid targets. For sinusoid targets, the position extrapolation model simulated tracking results more accurately for loop delays longer than 120 ms, thereby confirming its ability to compensate for sensorimotor delays. However, for pseudorandom targets, this advantage arose only after 300 ms, indicating that velocity information is unlikely to be exploited in this way during the tracking of less predictable targets. We conclude that negative feedback control of position is a parsimonious model for tracking pseudorandom targets and that negative feedback control of extrapolated position is a parsimonious model for tracking sinusoidal targets.

This study investigated clinical and process factors involved in a client-led psychological intervention (Method of Levels therapy – MOL). MOL offered 16 adolescents choice and control over attenda...

Different meta-emotion strategies are often categorised as either adaptive (e.g. compassionate care) or maladaptive (e.g. suppression). Yet some evidence indicates that the same strategy can be adaptive in one culture and maladaptive in another. We aimed to test whether meta-emotion strategies and their effects can in fact vary across different social contexts within the same individuals. A total of 140 students completed measures of meta-emotion strategies, satisfaction with life scale, and anxiety. Each scale was adapted for both the family home and the university home context. On average, the students had a lower level of interest in their emotions and adopted a tough control to a lesser extent when in the family home, compared to the university home context. At the individual level, some students used suppression more in the family home than the university home, whereas for others the effect was reversed. A series of multiple regressions showed the context specificity of meta-emotion strategies. Students who reported greater suppression of their emotions were more anxious, but only within the home context that these had both been measured. Yet, the relationship with life satisfaction was transferred across contexts; suppression in the family home (but not suppression at university) predicted less satisfaction with life at university. For other strategies (tough control, anger and compassionate care), their relationship with satisfaction with life at university was only predicted by the extent to which the participants reported using these strategies at university, and not in relation to their use in the family home.

Perceptual control theory (PCT) proposes that perceptual inputs are controlled to intentional 'reference' states by hierarchical negative feedback control, evidence for which comes from manual tracking experiments in humans. We reviewed these experiments to determine whether tracking is a process of perceptual control, and to assess the state-of-the-evidence for PCT. A systematic literature search was conducted of peer-review journal and book chapters in which tracking data were simulated with a PCT model (13 studies, 53 participants). We report a narrative review of these studies and a qualitative assessment of their methodological quality. We found evidence that individuals track to individual-specific endogenously-specified reference states and act against disturbances, and evidence that hierarchical PCT can simulate complex tracking. PCT's learning algorithm, reorganization, was not modelled. Limitations exist in the range of tracking conditions under which the PCT model has been tested. Future PCT research should apply the PCT methodology to identify control variables in real-world tasks and develop hierarchical PCT architectures for goal-oriented robotics to test the plausibility of PCT model-based action control.

Mood monitoring is widely used in the treatment and self‐management of bipolar mood swings. Typically, service‐users record their affective states in a paper or electronic diary over an extended period (e.g. weeks, months). The aim is to help people to achieve greater awareness and understanding of their affective states, which then enables them to better prepare and account for problematic changes in their mood, preventing escalation to mood episodes and relapse.

Architecture students have been reported to experience significant stress, yet little has been researched. This study aims to examine how architecture students experience and cope with stress. Twelve participants studying Architecture at bachelors and masters levels took part in individual interviews. Interviews were transcribed verbatim and analysed using thematic analysis. Three over-arching themes emerged: sources of stress in architecture studies, effects of stress and coping with stress. Participants reported of experiencing stress due to heavy and constant workloads, accepting the culture of working hard, subjective aesthetics, tutors and their critique. Stress experiences differed for year 1 and year 3 undergraduates. Students reported feelings of demotivation as a result. Many participants reported time management and making use of the supportive network of tutors and peers as coping strategies. Some participants acknowledged that things get better with time and the reward from producing a piece of work helped them to restore their motivation.

The purpose of this study was to test the feasibility and acceptability of a novel psychological therapy (Method of Levels) amongst adolescents experiencing psychological distress. An initial estimated effect size and a clinical significance analysis were undertaken which will help inform future studies. A case-series of 16 participants utilised the YP-CORE as a primary outcome measure. Data was collected at baseline, on completion of therapy (six months) and two and four months after completion of the therapy. Young people used a self-booking system to access sessions. Additionally, young people had full control over the content and length of the sessions. A total of 14 participants reported that the therapy was acceptable to them and 12 participants were retained for the entire course of the study. The self-booking system was successfully used with young people attending on average 6-8 sessions. Analysis of clinically significant change for the YP-CORE at therapy completion indicated that five students recovered and seven experienced no change; this was largely maintained at follow up. Effect size estimations were medium-to-large. Initial findings suggest that Method of Levels is a feasible and acceptable form of counselling for young people within the school setting. Moreover, positive preliminary effectiveness outcomes suggest that a randomised control study should be considered.

Background: Method of Levels (MOL) is a cognitive therapy with an emerging evidence base. It is grounded in Perceptual Control Theory and its transdiagnostic nature means techniques are widely applicable and not diagnosis-specific. This paper contributes to psychotherapy process research by investigating a key technique of MOL, asking about disruptions, and in doing so aims to explore how the technique works and aid the understanding of related techniques in other psychotherapies. Method: Conversation Analysis (CA) is applied to asking about disruptions in twelve real-life therapeutic interactions. Findings: Analyses explore how and when therapists ask about disruptions, with examples presented according to their degree of adherence to the MOL approach. The majority of identified instances project responses consistent with MOL aims; encouraging further talk, focused on the client’s problem, and with a shift to meta-level commentary. Also presented are examples of therapist and client influence on disruptions. Conclusion: The paper provides support for a number of MOL practices, with clinical implications and links to other psychotherapies highlighted.

Sleep problems are common with nearly one in three people reporting disturbed sleep. In line with guidelines, most people experiencing poor sleep in the United Kingdom are referred for cognitive and behavioral treatment approaches. A large proportion of these clients are seen by Psychological Well-being Practitioners (PWPs) delivering low-intensity therapy within Improving Access to Psychological Therapies (IAPT) services. The training of PWPs in the treatment of sleep problems is limited to sleep hygiene psychoeducation. The role that sleep hygiene psychoeducation plays in improving sleep quality is unclear, especially if used as a stand-alone intervention. The article introduces method of levels (MOL) as an alternative approach explaining sleep problems by transdiagnostic mechanisms. Two clinical cases are presented to demonstrate how MOL was implemented to support clients with the perceived sleep issue. This article adds to growing evidence that a transdiagnostic approach to helping people experiencing psychological distress is needed.

An integrative account of consciousness should have a number of properties. It should build upon a framework of nonconscious behavior in order to explain how and why consciousness contributes to, and addresses the limitations of, nonconscious processes. It should also encompass the primary (phenomenal), secondary (access), and tertiary (self-awareness) aspects of consciousness. A number of accounts have proposed a role for consciousness in the prediction of sensory input, yet these proposals do not address how organisms deal with multiple, unpredictable, disturbances to maintain control. According to perceptual control theory (PCT), purposiveness is the control of hierarchically organized perceptual variables via changes in output that counteract disturbances which would otherwise increase error between the current value and the reference value (goal state) of each perceptual variable. In PCT, reorganization is the process required for the adaptive modification of control systems in order to reduce the error in intrinsic systems that control essential, largely physiological, variables. The current article proposes that primary consciousness emerges from this system, and is sustained as secondary consciousness through a number of processes including the control of the integration rate of novel information via exploratory behavior, attention, imagination, and altering the mutation rate of reorganization. Tertiary consciousness arises when internally sustained perceptual information is associated with specific symbols that form a parallel, propositional system for the use of language, logic, and other symbolic systems. The hypotheses and initial research designs to test this account are provided. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Perceptual control theory states that behaviour controls perception; we act against disturbances in the environment to align hierarchically organised perceived aspects of the self and the world with neurally specified reference values. The diverse symptoms of psychopathology are each examples of loss of control, which are maintained by conflicting control systems, and effective interventions shift and sustain awareness to the source of the conflict to allow trial-and-error changes (reorganisation) in the parameters of the superordinate system to the conflict, until control is restored. Experimental, phenomenological, therapeutic and computational research has examined its mechanisms, and its mode of delivery has extended it from a client-led psychotherapy (method of levels) to brief training, group interventions and computerised modalities.

Have you ever heard someone say that they do not feel in control of their life? People tend to feel stressed or distressed when they cannot control things they feel are important to them, like feelings, a sense of self, or adherence to personal values. Control theory states that control is fundamental to well-being and to the healthy functioning of any person, group of people, or organization. The theory also states that changing behavior allows people to counteract disturbances (obstacles, challenges) that can threaten their ability to stay in control of their lives. So behavior change is at the very heart of well-being, at every moment of the day. This chapter focuses on how practitioners can draw on control theory to assist in making sustained behavior change that is beneficial to their well-being, such as helping parents manage their infant’s development, helping recovery from mental health problems, organizing education and discipline within schools, and managing organizations.

Behavioural experiments are an important technique in cognitive behavioural therapy. However, there exists little up-to-date guidance on how to conduct these in people with a diagnosis of bipolar disorder. This paper provides recommendations on how to conduct behavioural experiments in people with bipolar disorder. The aim is to upskill and empower clinicians to conduct behavioural experiments in this population. The paper combines the expertise of senior clinicians working in the United Kingdom developed in consultation with service users. The article starts by providing general advice on conducting behavioural experiments in bipolar disorder. It then offers specific examples of behavioural experiments targeting cognitions around the uncontrollability and danger of affective states, and related behavioural strategies, which have been implicated in the maintenance of bipolar mood swings. The article finishes by providing examples of behavioural experiments for non-mood related difficulties that commonly occur with bipolar experiences including: perfectionistic thinking, need for approval, and intrusive memories. Behavioural experiments offer a useful therapeutic technique for instigating cognitive and behavioural change in bipolar disorder. Conducted sensitively and collaboratively in line with peoples’ recovery focused goals, behavioural experiments can be used to overcome mood and non-mood related difficulties.

PURPOSE: To conduct a thematic synthesis to evaluate qualitative studies exploring individuals' experiences of psychological-based interventions for bipolar disorder (BD). METHOD: A systematic search of relevant databases (Web of Science, PsycINFO, MEDLINE, CINAHL) was conducted using predefined search terms related to 'Bipolar' 'Qualitative method', 'Psychological-based interventions' and 'Adults'. Studies meeting the inclusion criteria were selected and were then evaluated using established quality appraisal criteria. A thematic synthesis was used to synthesize the findings. RESULTS: From the thematic synthesis, nine analytical themes were derived from the 10 identified research studies. These were helpful and unhelpful aspects of the intervention, increased knowledge of BD, mood recognition, control of moods, change of perspective, mood stability, empowerment, improved relationships and lifestyle changes. CONCLUSIONS: Findings from the review suggest there were characteristics of psychological-based interventions that individuals with BD valued and which helped facilitate areas of positive change, such as feeling empowered and in control of their moods and other aspects of their lives. However, there were also elements that individuals did not find as helpful and therefore reflects the challenge of a one-size-fits-all model or plan of interventions, compared to a wider recognition of the individuals as being the agent of their recovery. Future qualitative research is needed to explore individual experiences across a range of psychological interventions, in order to further understand the therapeutic processes, which may facilitate recovery. PRACTITIONER POINTS: Psychological-based interventions for BD need to consider facilitating and measuring empowerment in individuals, rather than focusing just on mood stability. Clinicians with expertise and knowledge in BD should provide timely information to individuals and their families to help increase their understanding of the diagnosis.

In this study, we aim to increase our understanding of the self-reported sources of distress among people who have experienced first-episode psychosis. Following a systematic literature search, 33 relevant studies containing first-person accounts of first-episode psychosis were identified, which were synthesized using thematic analysis. Two interrelated superordinate themes were identified: intrapersonal distress and interpersonal distress. Participants reported multiple, diverse, and multifaceted sources of distress across both themes. These were substantially different from those routinely recognized and targeted in clinical practice. This review suggests that practitioners who maintain a stance of genuine curiosity about the potential sources of distress for this population will be perceived as more helpful. The findings also highlight the importance of being service user–led when planning and delivering mental health care. Additional clinical and research implications are discussed.

Background: Evidence for the efficacy of computer-based psychological interventions is growing. A number of such interventions have been found to be effective, especially for mild to moderate cases. They largely rely on psychoeducation and ‘homework tasks’, and are specific to certain diagnoses (e.g. depression). Aims: This paper presents the results of a web-based randomized controlled trial of Manage Your Life Online (MYLO), a program that uses artificial intelligence to engage the participant in a conversation across any problem topic. Method: Healthy volunteers (n = 213) completed a baseline questionnaire and were randomized to the MYLO program or to an active control condition where they used the program ELIZA, which emulates a Rogerian psychotherapist. Participants completed a single session before completing post-study and 2-week follow-up measures. Results: Analyses were per protocol with intent to follow-up. Both programs were associated with improvements in problem distress, anxiety and depression post-intervention, and again 2 weeks later, but MYLO was not found to be more effective than ELIZA. MYLO was rated as significantly more helpful than ELIZA, but there was no main effect of intervention on problem resolution. Conclusions: Findings are consistent with those of a previous smaller, laboratory-based trial and provide support for the acceptability and effectiveness of MYLO delivered over the internet for a non-clinical sample. The lack of a no-treatment control condition means that the effect of spontaneous recovery cannot be ruled out.

Computational models that simulate individuals’ movements in pursuit tracking tasks have been used to elucidate mechanisms of human motor control. Whilst there is evidence that individuals demonstrate idiosyncratic control tracking strategies, it remains unclear whether models can be sensitive to these idiosyncrasies. Perceptual control theory (PCT; Powers, 1973) provides a unique model architecture with an internally set reference value parameter, and can be optimized to fit an individual’s tracking behavior. The current study investigated whether PCT models could show temporal stability and individual-specificity over time. Twenty adults completed three blocks of 15 one-minute, pursuit-tracking trials. Two blocks (training and post-training) were completed in one session and the third was completed after one week (follow-up). The target moved in a one-dimensional, pseudorandom pattern. PCT models were optimized to the training data using a least-mean-squares algorithm, and validated with data from post-training and follow-up. We found significant inter-individual variability (partial η2: .464-.697) and intra-individual consistency (Cronbach’s α: .880-.976) in parameter estimates. Polynomial regression revealed that all model parameters, including the reference value parameter, contribute to simulation accuracy. Participants’ tracking performances were significantly more accurately simulated by models developed from their own tracking data than by models developed from other participants’ data. We conclude that PCT models can be optimized to simulate the performance of an individual and that the test-retest reliability of individual models is a necessary criterion for evaluating computational models of human performance.

Objectives Distressing and pleasant/positive voices (auditory verbal hallucinations) are common in both clinical and non-clinical voice-hearers. Identifying factors that contribute to emotional reactions to voices is essential for developing effective psychological interventions. Several theories propose that facilitation and interference with personal goals are important predictors of distress and well-being. This study examined whether voice-related distress is related to the degree to which voices interfere with personal goals, and whether pleasantness of voices is influenced by the extent to which they facilitate goals. Design Cross-sectional with clinical and non-clinical voice-hearers. Method Twenty-two clinical and 18 non-clinical voice-hearers completed interviews and self-report measures assessing (1) personal goals, (2) content, characteristics, and affective reactions to voices, and (3) ratings of the extent to which voices facilitated and/or interfered with achievement of important personal goals. Results Affective reactions were strongly correlated with measures of goal interference and goal facilitation. Regression analyses revealed that these associations remained significant when controlling for important covariates (e.g., participant grouping; content, frequency and duration of voices). Goal interference was specifically associated with distress, whereas goal facilitation specifically predicted perceived pleasantness of voices. Conclusions This study provides a novel perspective on the factors that might contribute to distress in people who hear voices. The findings suggest that perceived impact of voices on valued personal goals may be an important contributor of voice-related distress. We propose that clinical assessments, formulations, and interventions could benefit from the careful analysis of the perceived impact of voices on goals. Practitioner points These findings suggest that variability in voice-related distress is closely linked to the perceived impact of voices on personal goals. These strong effects observed highlight the importance of considering the role of personal goals in future research on the psychological mechanisms leading to distress associated with voice hearing. Psychological assessments may benefit from the careful exploration of the impact of voice hearing on valued goals, and interventions promoting control over personal goals may be explored as treatment options for clients with distressing voices.

Mental health problems present an increasing global disease burden making the development of effective and efficient psychological treatments an urgent public health priority. Despite the continued proliferation of treatments and large numbers of randomized controlled trials (RCTs), evidence suggests that pre-post effect sizes have been decreasing over time not increasing. Promoting RCTs as a gold standard of evidence has not been a useful strategy for advancing progress in the development of increasingly effective and efficient psychological treatments and has, in fact, created a divide between research and practice in professional psychology. To close this divide, other methodologies are needed that can assist in the rigorous development and evaluation of treatments in routine clinical practice. We outline some of the problems with using RCTs as the sole means of generating evidence for treatment effectiveness and efficiency and we use the development and evaluation of a transdiagnostic cognitive therapy to illustrate an alternative way of accumulating evidence through a much closer connection between research and practice. Ultimately, including other methodologies alongside RCTs that combine research and practice more seamlessly, will produce treatments of greater effectiveness and efficiency and help to reduce the global burden of mental health problems. (PsycINFO Database Record (c) 2017 APA, all rights reserved)

The central tenet of Perceptual Control Theory (PCT) is that ‘behavior is the control of perception’. From this tenet, a series of further elements are utiized to provide the necessary conceptual and mathematical detail for building and testing functional models of the behavior of humans, animals and purposeful machines. This chapter traces the elements of PCT, and their empirical scrutiny and critique, across multiple scientific disciplines to converge on a contemporary evaluation of the scientific status of PCT as an interdisciplinary theory of behavior. The chapter concludes with key recommendations for future research and the development of the theory.

On Friday 24th May 2013, William T. Powers, the founder of perceptual control theory (PCT), sadly passed away. This book is dedicated to him. I owe him a debt of gratitude. Without his scientific discoveries - my work, my world, and my life, would not make quite as much sense as they do today. Many of my colleagues have had a similar loss. And because Bill continued to be so generous with his time, patient in the face of persistent questions, and crystal clear in his reasoning, the loss was that much greater for all of us. There will no doubt be a story of Bill Powers' incredible life as an engineer, inventor, scientist, mentor, friend, father, brother, and son, but this book is not that book. This is the book that he wanted written by the many people with whom he had shared his vision. Each of them had gone on to share, test, or use his ideas in very different ways, in diverse academic fields, all with Bill's support and of course, feedback. I must particularly thank Alice Powers McElhone, Bill's sister, who through her business, Benchmark Publications, ensured the continued publication of Behavior: The Control of Perception, Bill's first book, as well as the publication of his subsequent works, Making Sense of Behavior and Living Control Systems I, II, and III. From 2013 to 2018, Alice nearly brought the publication of this final book in the Living Control Systems series to completion. We are extremely grateful to Elsevier for taking her good work to the finish line in time for her to witness the fruit of her labors.