This is an adventure book, a book about the Amazon, the Royal Geographic Society, and British explorer Percy Fawcett (and his family). It is the story of what happens when one searches for something based on hearsay. Reality takes over, and the real adventure is much less romantic than one would imagine. (Especially if they've watched movies like Raiders of the Lost Ark.) There are the affects of a jungle fraught with biting insects, maggots, sweat bees, piranhas and all sorts of other creatures which can make your life miserable. There are the unknown people who live there. Are they friendly or hostile?
What is it that leads others to continue this search, when the adventurers either return empty-handed or do not return at all?