This book provides the theoretical underpinnings, research, support, and techniques, to implement open-access/single-session therapy. Open-access services have moved beyond walk-in or drop-in services and expanded to on-demand teletherapy, virtual, or same-day scheduling. This book explains how best to implement single-session therapy in all such services, highlighting how this kind of therapy can reduce barriers to care. It includes chapters on training single-session therapists, global applications, and major obstacles. A team of expert contributors provide clinical examples and applications from around the world. This book is essential for clinicians and professionals offering or thinking about offering single-session therapy in open-access services.