contemporary prison systems – as punishment, for the prisoner’s own protection, as a tool for managing difficult prisoners and as part of the investigation or interrogation process – and some of the standards, safeguards and recommendations relating to the placement of prisoners and detainees in solitary confinement. Chapter Four examines international standards, research findings and recommendations regarding the design, physical conditions and regime in isolation units. Chapter Five addresses some of the ethical issues and dilemmas facing health professionals working in solitary confinement units, and Chapter Six briefly examines international, regional and national mechanisms for inspecting and monitoring solitary confinement units. Chapter Seven recaps some of the main issues and themes discussed throughout the Sourcebook. 1.3 Definition: what constitutes solitary confinement? For the purpose of the Sourcebook, solitary confinement is defined as a form of confinement where prisoners spend 22 to 24 hours a day alone in their cell in separation from each other1. Notwithstanding the different meanings attached to each of these terms in different jurisdictions, the term ‘solitary confinement’ will be used interchangeably with the terms ‘isolation’ and ‘segregation’ when describing regimes where prisoners do not have contact with one another, other than, as is the case in some jurisdictions, during an outdoor exercise period2. 1.4 Brief historic context Solitary confinement is one of the oldest and most enduring prison practices. Bar the death penalty, it is also the most extreme penalty which can legally be imposed on prisoners. Solitary confinement was first widely and systematically used on both sides of the Atlantic in the ‘separate’ and ‘silent’ penitentiaries of the 19th century, with the aim of reforming convicts. It was believed that once left alone with their conscience and the Bible, prisoners would engage in inner reflection, see the error of their ways and be reformed into law abiding citizens. It soon transpired, however, that rather than being reformed, many prisoners became mentally ill, and there was little evidence that the newly built, expensive prisons were more successful than their predecessors in reducing offending. Such criticisms, combined with growing prison populations and pressures for additional prison spaces, led to the dismantling of the isolation system in most countries by the late 19th century3. By then, however, solitary confinement had become a permanent feature of prison systems world-wide, used mainly as a form of short term punishment for prison offences, for holding political prisoners, for protective custody, and as a technique for ‘softening-up’ detainees, particularly those suspected of crimes against the State, before and between interrogation sessions. In addition to these ‘traditional’ uses, towards the end of the 20th century and at the beginning of the 21st, the use of long term, large scale solitary confinement returned in the form of ‘supermax’ (short for super-maximum security) and ‘special security’ prisons. These are large, high tech prisons, designed for long term and strict isolation of prisoners classified as high risk and/or difficult to control. This phenomenon is particularly evident in the United States, where the Federal Government and some 44 States operate at least one such prison, but similar units can now also 2 Sourcebook on solitary confinement: Introduction