"Restrictive housing, sometimes known as administrative segregation, is the practice of housing some inmates separately from the general population of a correctional institution and imposing restrictions on their movement, behavior, and privileges." This compilation of answers to frequently asked questions (FAQ) informs the reader about the concerns surrounding the use of restrictive housing (aka administrative housing, departmental segregation, and security housing units). Topics covered are: what restrictive housing is and how it works; why it is used; what the conditions are in restrictive housing; whether restrictive housing is different from solitary confinement; the commonality of restrictive housing use and whether its population is growing; why it is controversial; the fiscal impact of restrictive housing; and the impact of restrictive housing on mental health.