The author discusses the subject of self-harm in adolescence, considering the historical context of the development of its classification system. She presents an overview of theoretical fundamentals as well as models of behavior derived from them. Within the context of current research studies, she describes its prevalence, etiology, and comorbidity. The author specifies the basic protective and risk factors as well as all important influences. She presents the diagnostic tools currently used in research and clinical practice including the description of key approaches to prevention, therapy and treatment. This book includes the results of a unique research study mapping the lexical trace of the term self-harm in adolescents and the differences in perception of this term among those without own practice, with mediation and with personal, often repeated experience.