This must-have reference is a unique exploration of how the individual notion of ‘self’ and related constructs, such as early schemas and attachment styles, impact on psychopathology, psychotherapy processes and treatment outcomes for psychological disorders across DSM-5, such as depression, bipolar and schizophrenia spectrum disorders, anxiety and trauma, eating disorders, obsessive-compulsive and related disorders, autism, personality disorders, gender identity disorder, dementia and somatic problems such as chronic fatigue syndrome. It discusses the role of the concept of self in a wide range of existing theoretical and treatment frameworks, and relates these to real-life clinical issues and treatment implications. Emphasizing the importance of integrating an awareness of self constructs into evidence-based conceptual models, it offers alternative practical intervention techniques, suggesting a new way forward in advancing our understanding of psychological disorders and their treatment.