Showing The Manchurian Candidate by Richard Condon

Sgt Raymond Shaw is a hero of the first order. He's an ex-prisoner of war who saved the life of his entire outfit, a winner of the Congressional Medal of Honor, the stepson of an influential senator...and the perfect assassin. Brainwashed during his time as a POW he is a 'sleeper', a living weapon to be triggered by a secret signal. He will act without question, no matter what order he is made to carry out.

To stop Shaw, his former commanding officer must uncover the truth behind a twisted conspiracy of torture, betrayal and power that will lead to the highest levels of the government...