Narratives of convoy battles, technical treatments of U-boat types and even the memoirs of 'aces' have shed little light on the reality of routine, grime and terror experienced by the average U-boat crewman. This book explains what it was like to serve in a U-boat service itself. In researching the details of the men and officers who manned the U-boats the author has been able to discover where they came from, what occupations they held, their career-tracks in naval service, and the associated functions they performed on board. As a result new answers have been found to a number of questions which have never been systematically addressed. How many men served on U-boats? Were they all volunteers? Did morale truly remain high throughout the conflict? Did the U-boat force gradually deteriorate into a 'children's crusade'? What was the true relationship between the naval service and National Socialism? Based on questionnaires returned from over 1000 veterans, and sources at the U-Boot-Archiv in Cuxhaven, this book gives an account of what service in the U-boat arm was really like.