With Alan Turing as a background character, Robert Harris recreates the Second World War intelligence gathering machine at Bletchley Park that is the scene of a spy/crime investigation that shows the exposed heart of Britain’s class system as it ceased to be the dominant world power. There is quite a touch of Brideshead Revisited in this book as well as plenty of references to the social patterns of Edwardian times changing to a post imperial one that fully emerged in the 1950s.
The description of how complex encryption systems could be broken by exploiting human behaviour using mechanical (soon to be electronic) number crunching is fascinating. The crime and love stories were good too. Still, the lives and times were the real stars in the book.