You can see from the blurbs I've printed for you that some people liked the book, and it almost certainly has the distinction of being one of the longest private-eye novels ever published (350 pages of tiny print in the Popular Library edition pictured here). Frank "Lobo" Davies is vacationing on a small Greek island courtesy of a satisfied client. The place is crowded with hippies (the novel is very much of its time) and the idle rich. Lobo doesn't like the hippies, except for one beautiful girl. He doesn't like the idle rich much, either, except for one beautiful woman. Things move along, but I wouldn't say there was a "relentless pace" as one of the reviewers does. The first body doesn't turn up until page 110. This is one of those books that I think would have been better if trimmed a lot.
It's clear from the book's structure and its following of the conventions that Jones had read a lot of crime fiction, and the mystery is a good one, if a bit drawn out. In fact, spotting them was one of the pleasures of rereading the book.
It was fun to visit the '70s again, and Jones's use of local color is excellent. I don't know if Jones had any intention of making Lobo Davies a series character, though it seemed likely to me back in 1974 or so that he would. He died young, however, and if he'd planned a second book about Davies, he never got around to writing it. There's a more detailed discussion of the book and what Jones was up to here. Check it out.