This briefing note provides an overview of the social housing system. Except where stated otherwise, it focuses on the system in operation in England: many of the institutional and policy details differ in the other nations of the UK, and a full treatment of those is beyond the scope of this survey. However, some of the basic facts about social housing can be provided at a Great Britain or UK level, and we do that where possible (making clear the distinction). This note accompanies a detailed report analysing the choice over the level of rents charged to tenants in the social housing sector. Chapter 2 of that report, which provides some necessary policy and institutional background, is an abridged version of this briefing note.