Just started "Operation Drumbeat", by Michael Gannon. This is the story of the U-boat attacks off the U.S. coast, and pretty much the story revolves around U-123 and it's commander, Kaptain Reinhard Hardegen.
A good read, but too many pages are relegated to the biographies of high ranking U.S. and British (Army Navy) officers. I think they have no bearing on the subject of the book.