King Rat by James Clavell

The time is World War II. The place is a brutal prison camp deep in Japanese-occupied territory. Here, within the seething mass of humanity, one man, an American corporal, seeks dominance over both captives and captors alike. His weapons are human courage, unblinking understanding of human weaknesses, and total willingness to exploit every opportunity to enlarge his power and corrupt or destroy anyone who stands in his path.