The Oxford English Dictionary was crowd-sourced. A major contributor was Dr William Chester Minor. The chief editor, Dr James Murray, was particularly impressed by all the entries he was receiving from Dr Minor. After many failed attempts, Dr Murray finally managed to arrange to visit Dr Minor. It turned out that Dr Minor was an inmate at the Broadmoor Criminal Lunatic Asylum in Crowthorne. He lived almost all his remaining life at Broadmoor after being acquitted of murder due to insanity. From his room there, he produced definitions and supporting quotations for many thousands of words.
Title: The Professor and the Madman: A Tale of Murder, Insanity, and the Making of the Oxford English Dictionary
Author: Simon Winchester