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.