Shadow Divers: The True Adventure of Two Americans Who Risked Everything to Solve One of the Last Mysteries of World War II (Robert Kurson, Random House, 2004, 375 pages)

Fascinating story and wonderful adventure.

Shadow Divers tells the story of John Chatterton and Rich Kohler, two deep-sea wreck divers who in 1991 discovered the wreck of a World War II German U-boat lying at a depth of 230 feet off the coast of New Jersey.  For seven years, Chatterton and Kohler searched for the U-boat's identity.  Along the way, Chatterton's diving cost him a marriage, and Kohler's love for his German heritage helped turn him into a serious U-boat scholar. The two lost three of their diving companions on the wreck and their mentor, Bill Nagle, to alcoholism. The successful completion of their quest fills in a gap in World War II history and the fate of what is now known to be U-boat U-869.