Alan Nunn May was a nuclear physicist whose family lived in Barnt Green, Worcestershire, from 1913 to the late forties. He was engaged, during World War II, in Britain and Canada on top secret research into the harnessing of atomic power and collaborating with the Americans who were, at that time, engaged in the production of the atomic bomb. This book recounts the events surrounding his arrest, trial and subsequent imprisonment for contravening the Official Secrets Act. The reports and activities of MI5 on these events are described. Also included are the resultant protracted discussions in Cabinet and the tensions which arose between the British and American Governments. The narrative illustrates the long term effects of his actions on family, friends and colleagues.