This book explores California’s prison system in the context of vocational education reform. For prisons in the early twenty-first century, ideologies of evidence-based management meant that reform efforts to change the purpose of prisons from punishment to rehabilitation through vocational education required “evidence” to justify policy prescriptions. Yet who determines what constitutes evidence? In political environments, solutions are typically pre-conceived, which means that the nature of the evidence collected is also preconceived. As a result, key assumptions about outcomes are often wished away to show improvement and be accountable. Through a detailed analysis interspersed with stories from the authors’ experiences “behind the wall” among California’s prison population, the authors challenge the nature of evidence-based research as used in the prison environment. In the process they describe the thorny problems facing reformers.