Collaborative, participatory research has gained huge popularity in the past 20 years (building on the long-established tradition of action research). Here, academic researchers co-create knowledge with people with lived experience of the research topic (co-researchers) rather than carrying out research on them. With its democratic ambitions and transformative power, collaborative research sounds good! But in practice, "co-creation" is complex and full of tensions. What does co-creating knowledge entail in practice and how can we work with co-creation in collaborative research in ways that attend to the relational, ethical complexities? This book will present a critical, constructive approach to working with co-creation in the research process and the practices it is designed to further.