A Handful of Stars — Poul Anderson

Dominic Flandry is the Terran Naval Intelligence equivalent to James Bond. Dashing and debonair, he is deadly both to human women and his enemies. His foes are remarkable for their skill in manipulating people, but Flandry is matching them wit for wit. With his extremely good luck and keen mind honed from years of experience being a spy in various guises, Flandry is able to survive one near-fatal disaster after another. He seems indestructible and unmatched in all of the Terran empire. The Admiral of the Terran Navy even considers Flandry as one of the last brave and wholly honorable men in all Terra's Empire. And yet, for all of his successes in vanquishing enemies and seducing ladies, Flandry realized that he is not as hard as he think he is. His humanness was brought to the fore when he encounters enemies with whom he finds a connection with, and an utterly innocent lass whom--despite his feelings for her--he has to let go.