The previous 2016 edition, "E-Mental Health," shed light on the application of telecommunications technologies to deliver mental health services remotely to people in often underserved locations due to geographic distance, and cultural or language differences. This new edition on "Digital mental health" represents a similar concept as e-mental health. However, the paradigm has changed; underserved populations are no longer the exclusive focus. The experience of the COVID-19 pandemic has encouraged wider acceptance and application of the technology, expanding its use to both rural and urban areas. The expansive potential of digital mental health approaches is demonstrated in a variety of mental health contexts, highlighted through clinical examples and applications that introduce innovative strategies for technology integration. Moreover, the book outlines a framework for global cooperation, with the goal of cross-border exchange of expertise and knowledge. This book targets a broad audience, including mental health practitioners, medical and nursing students, academic researchers, technology experts, and health policymakers.