This book employs a careful, rigorous, yet lively approach to the timely question of whether we can justly generalise about members of a group on the basis of statistical tendencies of that group. For instance, should a military academy exclude women because, on average, women are more sensitive to hazing than men? Should airlines force all pilots to retire at age sixty, even though most pilots at that age have excellent vision? Can all pit bulls be banned because of the aggressive characteristics of the breed? And, most controversially, should government and law enforcement use racial and ethnic profiling as a tool to fight crime and terrorism?