I came to this novel through its film adaptation, The Pink Jungle. The star of the film, James Garner hated it. And so did Alan Williams. I, of course, liked it and still do, although it's difficult to find. Williams' novel (and the film) takes place in a fictional South American country, where Ben Morris has gone in search of adventure and to forget about the death of his wife. Prone to explosions of anger, Ben soon finds himself on the run for hitting a policeman. He then falls in with a group of treasure hunters that includes Stopes, a disgraced ex official with the British embassy, South African psycho Sammy Ryderbeit, and potential love interest Mel(anie). Off to find a stash of diamonds they go, traversing mountains, jungles, deserts, and volcanoes. It's actually fairly interesting. And I'm partial to adventure stories set in South America and the Far East. So Williams' book sets up perfectly for me.
If judging from this book alone, Williams is right below the first rank of postwar adventure writers. Among that group, I'd include Eric Ambler, David Dodge, Hammond Innes, James Ramsey Ullman, and perhaps Max Catto. Williams is right in a group below that. He was described as the next Ian Fleming when he published his first book. But he's far better than Fleming, creating grittier characters and more adventuresome situations. I've already downloaded eleven more of his novels.