This chapter provides an overview of the history of supermax prisons: facilities built across the United States in the 1980s and 1990s in order to hold “problem” prisoners, like gang members, the seriously mentally ill, the extremely violent, and those sentenced to death, in solitary confinement for months and years at a time. Since nearly every state opened one of these facilities in the late twentieth century, prisoners have litigated the constitutionality of the harsh conditions: no human contact, 24-hour fluorescent lighting, limited time outdoors. In spite of these conditions, supermaxes were not just another popular tough-on-crime innovation; state (not federal) prison administrators designed the first supermaxes with little public knowledge or oversight, in response to organized protests in prisons in the 1970s and 1980s. Although prisoners have sought to challenge these facilities, litigation has, in many cases, played a legitimizing in the history of supermaxes.