As I've noted numerous times, back when I was a young'un, I was a science fiction fan, devoted to Asimov, Heinlein, and Clarke, all of whom got their start in the 1930s and 1940s. But I also liked Roger Zelazny, a "newer" author who became famous in the 1960s. He won a passel of Hugo and Nebula awards, but died far too young in 1995. (Specifically, he was—gulp—the same age I am now. Which, dear reader, is the very definition of "far too young.")
This book's manuscript was discovered recently by Zelazny's agent; it was apparently written in the early 1970s. It's not remotely science fiction, and it's published by "Hard Case Crime", a publisher devoted to retro paperback fare with wonderfully lurid cover art reminiscent of the pulp on bus station book racks 40-50 years back. (This book's cover, as you'll note over there, has the hero armed with a machete, sheilding a scantily-clad dame, hiding in the jungle from bad guys bearing automatic weaponry. Something we all can relate to.)
Despite the low-rent treatment, I had a great time reading it, revisiting Zelazny's prose style out of its usual SF/fantasy setting.
The protagonist is Ovid Wylie, an international art thief and smuggler gone legit, running a New York City gallery. But his past catches up with him pretty quickly: his ex-partner has become a murder victim, and dumped on his premises. The CIA uses the crime as leverage to wangle Ovid into investigating a renegade priest who has apparently absconded with Vatican funds; his detective work takes him to Rome and Brazil, and (of course) Ovid's either in peril, escaping from peril, or about to do something that will place him in peril.
It reads as if this might have been an effort by Zelazny to develop a series hero, something in the Travis McGee line. That didn't happen, unfortunately.