Correctional policies for Islamist violent extremist offenders are often based on the premise that prisons can be hotbeds of radicalization. The perception that inmates are susceptible to violent extremist belief systems has given rise to a fervent international public, political, and scholarly debate and has led to the introduction of drastic, often expensive policies to counter the threat of prison radicalization. But is the introduction of these policies justified?A key question is whether violent extremist offenders should be concentrated in separate high-security prisons, or whether they should be integrated into the mainstream inmate population. Prisoner Radicalization and Terrorism Detention Policy argues that concentration strategies to manage violent extremist offenders are often flawed - based on untested, potentially false assumptions that are rooted in fear rather than in facts. Little academic evidence has been produced that can valuably inform policy making in this area. As a result, policies to detain violent extremist offenders may be inadequately tailored to achieve their objectives, and could even lead to an intensification of the violent extremist threat.This book is the first to present a detailed and systematic case study of the decision-making and implementation process behind terrorism detention policy. It will be essential reading for students, scholars and policymakers researching criminal justice, terrorism and extremism.