The Secret War by Max Hastings

This highly ambitious history of global intelligence during The Second World War is well-written and thoroughly researched with interesting anecdotes about strange characters, such as Sorge, a hard-drinking and womanising Russian who set up a spy network in Japan and the Maverick academic Hugh Trevor-Roper. However, I have decided not to go on with it. It's just too long and I am mostly interested in the French Resistance.