All My Sins Remembered(1977)

Joe Haldeman

Otto McGavin is peaceful and idealistic by nature, an Anglo-Buddhist, who seeks employment with the Confederacion because he believes in it and its mission to protect the rights of humans and nonhumans. The only problem is that the Confederacion needs him as a Prime Operator for its secret service, the TBII, and the TBII wants Otto as a spy, a thief and an assassin. It's not, of course, a problem for the Confederacion, which simply uses immersion therapy and hypnosis for Otto's training, and then sends him out in deep cover on a variety of dangerous missions on a number of bizarre worlds. But for Otto, it's a different what he has to witness and what he is forced to do take a terrible toll on him ...