Adolescence, derived from the Latin adolescere, that is, to grow, has a long history, but its emergence as a major social, pedagogical, and academic concern may be traced to the second half of the 19th century. From then on, despite ongoing disputes about its characteristics, scope, and relevance, adolescence has established itself as a natural and allegedly universal feature of the process of growing up, embodying evolving conceptions about the transition from childhood to adulthood. This entry examines the rise of adolescence as a category of discourse and intervention and explores the controversies that have accompanied it.