A Legacy of Spies - John Le Carre

Peter Guillam, former disciple of George Smiley in the British Secret Service, has long retired to Brittany when a letter arrives, summoning him to London. The reason? Cold War ghosts have come back to haunt him. Intelligence operations that were once the toast of the Service are to be dissected by a generation with no memory of the Berlin Wall. Somebody must pay for innocent blood spilt in the name of the greater good .