The optimum level of violent or aggressive play in sporting contests is an empirical issue and this book contains chapters on violence and aggression in sports, concentrating on the reasons for the existence and persistence of such behavior. Following a chapter devoted to the history of violence and aggression in sports, subsequent chapters are designed to cover the breadth of international professional sports including American football, soccer, ice hockey, basketball, baseball, auto racing, and fighting sports. Each chapter will contain econometric analysis of violence and aggressive play in a given sport. The individual chapters will examine whether or not a given sports league or governing body should intervene to reduce violence, and where intervention is warranted, extent of appropriate interventions is evaluated. .