Principles of Change demonstrates that the ideas and observations of many clinicians about psychotherapy (how change is facilitated or hampered, with whom and by whom, etc.) can shed light on how research findings can best be implemented in practice. Edited by renowned psychotherapy researchers and with chapters authored by expert psychotherapy practitioners, the book creates a new collaboration based on direct and bi-directional communication between scientists and clinicians who draw on their respective knowledge and expertise, and that will lead to synergetic methods for understanding and improving psychotherapy.