The Blue Nile.

In the first half of the 19th century, only a small handful of Westerners had ventured into the regions watered by the Nile River on its long journey from Lake Tana in Abyssinia to the Mediterranean -- lands that had been forgotten since Roman times, or had never been known at all. In The Blue Nile, Alan Moorehead continues the classic, thrilling narration of adventure he began in The White Nile, depicting this exotic place through the lives of four explores so daring they can be considered among the world's original adventures -- each acting and reacting in separate expeditions against a bewildering background of slavery and massacre, political upheaval, and all-out war.