The most punitive era in American history reached its apex in the 1990s, but the trend has reversed in recent years. Smart on Crime: The Struggle to Build a Better American Penal System examines the factors causing this dramatic turnaround. It relates and echoes the increasing need and desire on the part of actors in the American government system to construct a penal system that is more rational and humane.

Author Garrick L. Percival points out that the prison boom did not naturally emerge as a governmental response to increasing crime rates. Instead, political forces actively built...