The Fraternity of the Stone (Morrell, David) Unabridged edition

Drew Maclane was a star agent - until the day the killing had to stop. He withdrew and for six years lived the life of a hermit in a monastery. But someone has tracked him down, leaving a trail of corpses. Someone who knows all about him, who knows how to draw him back into that electrifying world where no one is as he seems, and where life's most horrifying and harrowing game is played....