The main theme of this Sourcebook is that solitary confinement harms prisoners who were not previously mentally ill and tends to worsen the health of mentally ill inmates. Solitary confinement should, therefore, be kept to a minimum. When it is used, the level of meaningful social contacts with staff, other inmates, and visitors should be maintained. The first chapter addresses issues of definition, provides the historical context for the use of solitary confinement, and outlines the legal and regulatory framework for the operation of prisons and the treatment of prisoners. Chapter 2 examines the documented health effects of solitary confinement, both physical and psychological, and identifies the features of solitary confinement that make it so damaging to inmate health. Chapter 3 examines the various roles of solitary confinement in contemporary prison systems. These include punishment, inmate protection, as a tool for managing difficult prisoners, and as part of an investigation or interrogation process. This chapter also addresses some of the standards, safeguards, and recommendations regarding the placement of prisoners and detainees in solitary confinement. Chapter 4 presents international standards, research findings, and recommendations regarding the design, physical conditions, and regime for isolation units. Chapter 5 considers some of the ethical issues and dilemmas facing health professionals who work in solitary confinement units. Chapter 6 briefly examines international, regional, and national mechanisms for inspecting and monitoring solitary confinement units; and Chapter 7 reviews some of the main issues and themes discussed in the Sourcebook. A 90-item bibliography