This book offers a comprehensive overview of the central theoretical tenets of Acceptance and Commitment Therapy (ACT), guidance on key practical applications of the approach, and reflection on the strategic issues inherent to the delivery of this psychological intervention.This thoroughly revised edition explains and demonstrates the range of acceptance, mindfulness, and behaviour change strategies that can be used in the service of helping people increase their psychological flexibility and wellbeing. Divided into three main parts, the book provides the reader with a solid grounding from which to develop their delivery of ACT-consistent interventions. This new edition also includes an update of the research literature and a review of new developments, techniques, and approaches within ACT theory and practice, fortified with a greater appreciation of diversity issues, such as the application of ACT across different groups and cultures.This book will be of interest to students and practitioners of ACT from a range of disciplines spanning clinical, organisational, coaching, counselling, and psychotherapy settings.