Joseph John Poyer was an American author whose fiction first appeared in Analog magazine with Mission 'Red Clash' (1965). His novels include technothrillers such as Operation Malacca (1968) and North Cape (1969), and the alternate-history work Tunnel War (1979).
I picked this one up at a used bookstore based on the cover, which promised old 1970s adventure. It is a straightforward action/adventure book with hidden nazi gold, double-crossing, and surviving the skin-of-your-teeth firefights. The writing was quite good, with the descriptions and excellent scenery. The collapsed tunnel fist fights and downpours in the jungle shoot-outs were projected on my mind like I was watching Indiana Jones. Unfortunately, I did find parts of the book slowly trudged along, and an entire section felt out of place and unnecessary. It was still fun, and the cover art promise was satisfied.