In this book, Brian Forst takes a fresh perspective on the assessment of criminal justice policy, examining the prospect of assessing policies based on their impact on errors of justice: the error of failing to bring offenders to justice, on the one hand, and the error of imposing costs on innocent people and excessive costs on offenders, on the other. Noting that we have sophisticated systems for managing errors in statistical inference and quality control processes and no parallel system for managing errors of a more socially costly variety - on matters of guilt and innocence - the author lays the foundation for a common sense approach to the management of errors in the criminal justice system, from policing and prosecution to sentencing and corrections. He examines the sources of error in each sector, the harms they impose on society, and frameworks for analyzing and reducing them.