This collection bridges the voices of international scholars and adopted persons to share knowledge about clinical practice with adopted people in adolescence and early adulthood. Coming at a time when countries are beginning to focus on adoption reform, this handbook is the first to address not only the external, systemic contributions to their developmental complexities but also the underlying, internal meanings of being adopted as children become adolescents and mature into adulthood. It explains how adopted clients differ from those not adopted and emphasizes the need for clinical research on adopted people in this older age group. Exploring how clinicians can understand their client’s clinical needs, it offers specific protocols and frameworks for assessment and necessary modifications in language and treatment. With a foreword by Miriam Steele, chapters examine the legal and sociopolitical cultures, policies, and practices in which adoption is embedded, calling for broad systemic change. Embracing theoretical, conceptual, and global perspectives, this handbook is written for clinicians in all disciplines, at all tiers of practice, administration, and training, identifying the key roles they can potentially play in expanding and better focusing our understanding of the psychology of being adopted.