In a July 14, 2015, speech at the NAACP National Convention, President Barack Obama announced that he had asked Attorney General Loretta Lynch to conduct a review of ‘the overuse of solitary confinement across American prisons.’ The President directed that the purpose of the review be not simply to understand how, when, and why correctional systems isolate certain prisoners from the general inmate population, but also to develop strategies for reducing the use of this practice across our nation’s criminal justice system. Over the past several months, a team of senior officials at the U.S. Department of Justice met regularly to study the issue of solitary confinement—or ‘restrictive housing,’ to use the more general corrections term—and formulate policy solutions. This report is the culmination of that review.