Trevanian’s protagonists all fit the same mold. They’re geniuses, masters of many fields, and they disdain basically everyone around them. James Bond, but somehow even more of a dick. Former assassins who just want to be left alone to their specific interests (gardening, mountaineering, art collecting, lovemaking) yet each time are leveraged into doing “one-last-job” for whichever faceless monolithic espionage unit comes calling this time.
And yes, the author is Trevanian, one word, one badass pseudonym. Glancing at his Wikipedia page perfectly describes him: “the only writer of airport paperbacks to be compared to Zola, Ian Fleming, Poe and Chaucer.” The novels are pulpy and the writing fits well with his protagonists: witty, cynical, and to the point.
I’ve read two of his spy novels and I’m in the middle of my third. The first was Shibumi, which was straight down my fucking strike zone . Here’s a bit from Amazon’s summary: “Hel survived the destruction of Hiroshima to emerge as the world’s most artful lover and its most accomplished—and well-paid—assassin. Hel is a genius, a mystic, and a master of language and culture, and his secret is his determination to attain a rare kind of personal excellence, a state of effortless perfection known only as shibumi.” This is probably my favorite of the three, but just slightly over the next one.
The second, The Eiger Sanction is incredibly similar, but with enough of a twist to keep it fresh.
This time our genius playboy spy is “an art professor, a mountain climber, and a mercenary, performing assassinations (i.e., sanctions) for money to augment his black-market art collection”. I’m now reading the follow-up, The Loo Sanction, which isn’t as good as the first two, but is still thoroughly entertaining. The Sanctions are designed more as direct spoofs of Agent 007, but are damn fun in their own right.
If you’re into the spy genre at all, I think you’ll dig Trevanian.