This book is about some deep sea divers who dive shipwrecks. They wound up finding a UBoat off the New Jersey coast, 230 feet below the surface. Inside the submarine, they discovered human remains. There were no identifying marks that they could see, and there was no record anywhere of there being a Uboat in this area. The work they put in to find out the identity of this ship and its crew was staggering. This was a very interesting book to read. I loved it.