Windfall, by Desmond Bagley
Although the adventure starts out in the United States, it ultimately moves via London to Kenya, which the author knew well since he lived and worked there for years. The result of this is a very authentic picture of Kenyan scenery, weather and wildlife, and although the book was published in the 1980s, perhaps little has changed with those factors even today.
Bagley paints his characters very carefully and they fit into his story accurately. He backs every situation up with authentic material, so the reader really feels included in the tale. If the author says that a hippopotamus can bite a man in half, the reader is obliged to believe him.
The story is the typical one of greed, where a variety of characters vie for a large slice of a huge sum of money, with the good guys pitted against the bad. The puzzle is for the goodies (and the reader) to figure out which are the real baddies and exactly what they are after, and to attempt to get the money into the right hands.
There is much adventure in the Kenyan wild country, where men are not the only opposition. The terrain and its four-legged inhabitants have no respect for modern human beings, who generally have very little hope of survival when left without the support of sophisticated materials and wheels. And we are taken for a ride in a balloon, expertly handled, for a bird’s eye-view of this unique country.
The protagonists wind up on a very small island surrounded by a snake, hippo and crocodile-infested lagoon, followed by a secret underground bunker where at last the heroes get to find out who the real bad guys are and what this is all about.
A good story.