The Guidelines for Good Practice of the European Association for Language Testing and Assessment (EALTA) stress the importance of collaboration between all parties involved in the process of developing instruments, activities and programmes for testing and assessment. Collaboration is considered to be as important as validity and reliability, providing a crucial prerequisite for responsibility and respect for students. The papers, covering a range of topics that consider both realities and prospects of collaboration, were originally presented at EALTA conferences from 2008 to 2010. Contents include: (1) Foreword (John H.A.L. de Jong); (2) Issues and Challenges in Combining SLA and Language Testing Research (Riikka Alanen, Ari Huhta, Scott Jarvis, Maisa Martin, and Mirja Tarnanen); (3) Replicating Results from a CEFR Test Comparison Project Across Continents (Jamie Dunlea and Neus Figueras); (4) Adaptations of CEFR Descriptors to Local Contexts (Karin Vogt); (5) Co-operation in Europe: "Local" Practices and "Global" Requirements (Carole Sedgwick); (6) Working with the CEFR: The Bilkent Linking Project (Carole Thomas); (7) A Collaborative Approach to National Test Development (Gudrun Erickson and Lisbeth Aberg-Bengtsson); (8) Comparing the Hungarian School-Leaving Examination with International Language Examinations (Gyorgyi Egyud, Zoltan Kiszely, and Gabor Szabo); (9) Local Institution, Global Examination: Working Together for a "Co-certification" (David Newbold); (10) Matura's Rocky Road to Success: Coping with Test Validity Issues (Slobodanka Dimova); (11) Synergies and Tensions in Computerised Language Testing (Anders Johannessen Fikke and Hildegunn Lahlum Helness); (12) Translation Assessment Methodology and the Prospects of European Collaboration (June Eyckmans, Winibert Segers, and Philippe Anckaert); (13) Preliminary Collaborative Steps in Establishing CEFR Sign Language Levels (Laura Sadlier, Beppie van den Bogaerde, and Joni Oyserman); (14) Collaboration in Understanding Results--Self-assessment of EFL Writing (Anne Dragemark Oscarson); and (15) Effects of CLIL Teaching on Language Outcomes (Lisbeth M. Brevik and Eli Moe).