Brookwood Hospital was established in 1867 by Surrey Quarter Sessions as the second County Asylum and from then until its closure in 1994 served as the leading mental hospital for the western half of the county. During World War II, it also served as an emergency war hospital.

The surviving records are extremely abundant and provide a very full and rich picture of the government and administration of the hospital and of the medical care provided.
They also reflect the functioning of this vast institution as a self-contained community with workshops providing practical and therapeutic training, a farm providing food for internal consumption and sale and a programme of entertainments.