In this thesis I develop an innovative theoretical and methodological approach for exploring interconnections between language, literature and culture at the fin de siècle in Germany and Sweden, focussing on the concept of decadence as the mainspring guiding the elaboration of my approach and analyses. The fin de siècle is characterised as a moment of acute and significant upheaval, instability and uncertainty. Foundational aspects of social and subjective self-experience and self-understanding undergo profound transformation at this time as core cultural institutions, conventions and values become destabilised and opened up to reformulation. In particular, a sense of hopeful optimism and faith in the potentialities of humanity and human ingenuity jars with a concurrent horror at the ruthlessness, hardship and unrest through which these possibilities are unfolded, and with a sense of anxiety surrounding the uncertainties of a self-conscious and open future. How to conceptualise, theorise and analytically manage and approach these ambivalences and tensions is at the heart of the drive underpinning this research. Decadence, especially in the German and Swedish cultural contexts, emerges as a particularly problematic and revealing concept to explore the ambivalences and contradictions of the fin de siècle as troubled and troubling time. Decadence is a notably widespread concept at the fin de siècle, yet this diffuseness poses theoretical and analytical dilemmas. There is a conflicted irresolution between recognising the prevalence of the concept at the time as significant and meaningful, and yet the profound ambiguity and liminality of the term frustrates its use as critical concept in analyses. Decadence is dismissed as too unstable and questionable, and the fundamental indeterminacy of the term often becomes separated out and collapsed in order to make it analytically manageable. It is at this analytical juncture that this project is situated - how to reconcile the notable saliency and significance of decadence with its profound ambiguity and instability. The main drive underpinning this project is therefore to develop an original theoretical and methodological approach that explicitly, flexibly and productively addresses the fundamental ambiguity and liminality of decadence at the fin de siècle, an approach in which the instability and ambiguity of the concept become the springboards for analysis rather than its limitation. In the first half of this thesis, I translate critical issues and insights on decadent ambiguity and instability at the fin de siècle into theories of (re)signification and meaning. Reframing decadence in terms of theories of meaning and (re)signification enables me to theorise the significance and meaningfulness of the ambiguity and liminality of decadence as playing a particular semantic function - as opening up semantic resources and strategies for destabilising, exploring and reformulating different possibilities of meaningful configuration. In particular, a theoretical and methodological approach to meaning and signification that combines systems theory, discourse theory and computational approaches to textual analysis facilitates a systemic, flexible and productive approach to decadent ambiguity and liminality at the fin de siècle in which discursive patterns and tensions can be explored across different scales and lines of analysis. Systems theories formalise the shifting interactions and interrelations of complex phenomena. These theories can therefore productively address the structural tensions of decadence and the way in which it interrelates different culture spheres and levels. The discourse theory of Laclau and Mouffe is especially useful for theorising moments of acute cultural instability as moments of particularly visible and intense processes of (re)signification. As a constructionist theory, discourse theory offers theoretical resources for reconceptualising the relations between different cultural practices through meaning and signification. A discourse perspective theorises meaning as cultural practice in which a shared cultural reality is elaborated through patterns of cumulation and interrelation that draw on shifting repositories of potential cultural resources and that are perpetually destabilised and restabilised into different arrangements and configurations. Computational deformances, enabled by word frequency queries and topic modelling, can visualise and re-present these latent patterns of cumulation and interrelation within and across texts in ways that would not be representable and perceptible otherwise. Furthermore, the malleability of computational methods can allow for the tracing and comparing of different lines of inquiry at different scales of analysis thereby facilitating an exploratory, speculative and defamiliarising analytical process through the iterative movement between local and systemic scales of analysis and different lines of inquiry. In the second half of this thesis, this approach is unfolded into analyses of texts written between the 1870s and the 1910s by Thomas Mann, Friedrich Nietzsche, Hjalmar Söderberg and August Strindberg. These are then contrasted to investigations of patterns of discursive clusters and tensions within and across corpora of research literature on decadence and associated concepts published between the 1920s and the 2010s. These analyses explore and substantiate how conceptualising decadence as opening up discursive strategies and resources that play out dynamics and possibilities of (re)signification can bring to light productive avenues of further investigation.