Unbeknownst to the majority of the public, isolation chambers in prisons have proliferated over the past few decades to the point where 100,000 people or more are being held in long-term solitary confinement on any given day in the United States. Even less known by the average citizen is the serious threat supermax prisons and control units pose to the country as a while. They not only severely affect those entombed inside them, but also the guards who work in them, and the communities those prisoners and guards return to. Control Units and Supermaxes: A National Security Threat details those affects and threats as well as the experiences of several states' efforts to reconsider the practice.