Sudhir Venkatesh walked into the worst housing project in Chicago carrying a clipboard, unknowingly approached members of the notorious crack-cocaine gang the Black Kings, and gathered his first data as a sociology grad student at gunpoint. In his penetrating book Gang Leader for a Day, the Columbia prof recounts his time infiltrating and, yes, overseeing, for one day, Chicago's gangbangers. His unexpected friendship with gang leader J.T. takes you deep inside in the very first chapter.