This is a review of what is and is not known about neighbourhoods and communities. It starts to analyse the characteristics of neighbourhoods, including how they are defined and the role of the local public realm in bringing them together. It sketches some approaches, lessons and issues for community empowerment and governance, and frames questions for the future. This paper was first published by the Young Foundation in 2006 as part of the Transforming Neighbourhoods programme. It has been updated and revised for publication in 2010. Transforming Neighbourhoods was a research and innovation consortium on neighbourhood governance and empowerment that ran from 2006 to 2008. It brought together government departments, community and research organisations. Partners included the Department for Communities and Local Government, the Home Office, the Joseph Rowntree Foundation, CABE, The Community Alliance and 15 local authorities including Birmingham, Camden, Haringey, Knowsley, Lewisham, Liverpool, Newham, Sheffield, Staffordshire, Suffolk, Surrey, Tower Hamlets, Wakefield, Waltham Forest and Wiltshire.