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 "e;evidence"e; 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 "e;behind the wall"e; 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.