This short list of published sources and web links are all connected to the history of asylums. The books are available from libraries, and the web links on line. Please add to them if you can.
Barbara Taylor’s book has a useful select bibliography.
Roy Porter, A Social History of Madness: Stories of the Insane (London, 1987)
Barbara Taylor, The Last Asylum: A Memoir of Madness in Our Times (London, 2014).
David Clark, The Story of a Mental Hospital: Fulbourn,1858-1983 (London, 1996)
Wise, Inconvenient People: Lunacy, Liberty and the Mad-Doctors in Victorian England (London, 2012)
Mark Davis, Marina Kidd, Voices from the Asylum, West Riding Pauper Lunatic Asylum (2013)
First hand accounts of asylum life in twentieth century Britain, from the Mental Health Testimony Archive in the British Library Sound Archive.
The Institute of Conservation has some useful leaflets about caring for heritage collections, including archives.