This book offers an approach to psychotherapy research that is based on a partnership between clinicians and researchers. It describes how to conduct practice-oriented research (POR) by presenting studies by eleven groups of who have been involved in POR around the world. The book provides tools to help clinicians be active participants in conducting clinically relevant studies, and set the agenda for future research. It seeks to foster collaboration between researchers and practitioners, generating knowledge that can improve our understanding of the process of change and the impact of psychotherapy. This book was originally published as a special issue of Psychotherapy Research.