Alan Caillou had quite a career, not just as a writer but as a soldier, spy, actor, and writer. My favorite among his works was the Assault series, six books published by Avon in the late 1960s. Their protagonist is Cabot Cain, a genius who knows all about everything (he teaches at Stanford, among other places); stands 6 feet, seven inches tall; speaks just about any language you can think of; is quite the world traveler; and is (of course) irresistible to women.
All the books have exotic settings, and Caillou was expert in conveying the local color. The descriptions are so vivid and so crammed with specific details that it's hard for me to imagine that he wasn't sitting in Macao when he wrote Assault on Ming (which was nominated for an Edgar for best paperback).
Also, all the books are propelled by Cain's energetic first-person narration. In Ming, he's hired to find the missing daughter of a wealthy man. So far, nothing new. In fact, there's really nothing new in the book, but it's the execution that's fun. Cain doesn't just know everything. At times he's compelled to share. Working his way though a tunnel, he encounters an iron grille:
The heavy bars were welded at the cross-joints and cemented at the right-angled corners into the granite in which the vents had been cut. . . . It looked as though the cement were Portland, and the fresh waters on the coast here are heavily alkalai -- a bad combination; they should have used Portland-Pozzolana, which would have given better adhesion.
But it's the next paragraph I like best. I won't quote it, but in it Cain describes how he's going to pry the bars loose with an anchor. He gives the angle at the fulcrum, the cooefficient of shrinkage in the cement (0.0765), the pressure required at the end of the lever both with and without taking into account the curve of the bill, and more. There's stuff like this in all the books, and I found it great fun.
Caillou died only a couple of years ago, but I suspect very few fans of adventure fiction remember him at all. That's a shame, because he did several other entertaining series. Check 'em out.