Sleepers hide in plain sight. Spies, double agents, lovers, mothers, writers. They wear smiling masks, turn up the collars of their raincoats, write in invisible ink, wear many disguises, and consort with the enemy. Some of them sleep for years, like Sleeping Beauty, waiting to be summoned. Some forget what they are hiding from, or where their real allegiances lie. Sleeper examines loyalty and dishonesty, class and power, the spies who were caught - like Mata Hari and Ethel Rosenberg - and those who got away - like the Cambridge Spies - seen through the eyes of friends, family and lovers (including the four wives of Kim Philby). This is a book about secrets and lies, divided loyalties and double lives, about waiting to come in from the cold.