Anthony Blunt, aesthete, communist, homosexual, MI5 agent and Soviet mole, was Surveyor of the King's Pictures and Director of the Courtauld Institute. Betrayed in 1963, he voted for Margaret Thatcher in 1979. Late that year, she was to expose his treachery and strip him of his knighthood. While the other Cambridge spies (Philby, Burgess and Maclean) subordinated their lives and careers to espionage, Blunt had a separate passionate existence. His reputation as an art historian was second to none: he made an enormous contribution to the establishment of art history as an academic discipline; his volumes on Poussin, French and Italian art and old master drawings are still in print and some are still set texts. At the Courtauld he trained a whole generation of world-class academics and curators. A human paradox, Blunt was a highly-regarded member of the British intelligentsia but his life as such and as a member of the British homosexual subculture of the 30s, 40s and 50s has hardly been explored. Miranda Carter's biography shows how his life vividly illustrates certain key themes and moments of the 20th century. Blunt led two totally discrete lives, he was a set of permanent contradictions.