Hennissart writes authoritative spy-fi and this one begins with the termination of a US presidential adviser at the command of a monstrous woman, Ana Pecs. With the reluctant collaboration of her KGB subordinate, Rappaport, who then has no place to come in out of the cold. Most of the action--and implacably active it is--deals with Rappaport's attempt to stay alive and get away, jeopardized by his friendship with a young woman. It's expertly timed and maneuvered, but Rappaport, aloof and opaque, won't warm your hands. Perhaps that's the specific ""incalculable factor"" of the hero/antihero, agent/double agent.