This module begins with the questions, what is youth, and, why have societies always positioned youth either as "troublesome" or "in trouble"? We go back to the 19th Century and the 'invention of adolescence' to explore the roots of the notion of youth as a social problem, and to begin to identify the ways in which societies have both theorised and dealt with forms of youthful indiscretion. These themes are then brought right up to date, as we examine the changing ways in which criminological theories and juvenile justice systems have approached youth crime in the UK and USA up to the early 21st Century. In this middle part of the module, we work through the punitive and preventive turns, the application of right and left realist approaches to crime, and the position of diversion in approaches to juvenile justice. The latter part of the module then broadens the scope of our subject matter by adopting an international comparative perspective, asking, in what ways, and why, have different countries adopted different approaches to the youth crime question? How are these different approaches connected to wider political and economic shifts in global governance, and to the changing shape of welfare states? This comparative perspective is further applied within national contexts, as we explore wide regional variations in approaches to youth crime, and question what is driving them.