This book is the definitive and most up-to-date guide to the elements and adaptations of interpersonal psychotherapy (IPT) and has been written by its developers and trainers. Researchers who want to adopt or test this evidence-based psychotherapy treatment or clinicians who want to include it in their practice can use this book as their foundation. While the procedures are presented for adult depression, many adaptations to different populations and settings are discussed: for pregnancy and the postpartum period, adolescents, the elderly, medical patients, and patients with dysthymia, bipolar disorder, substance use disorder, eating disorders, anxiety disorder, trauma, and borderline personality disorder. Throughout, the same four problem areas are used: grief, role disputes, role transitions, and interpersonal deficits (social isolation). A chapter on cross-cultural adaptations is provided. New formats, training, and research are described. Case examples are included throughout the book to illustrate the methods.