^ An excellent read. I have both volumes (hardback versions) stored for safe keeping but could never understand why volume two, The Hunted is always so much more expensive.
I consider this the daddy of them all. A bit technical in places and not cheap. In fact back in the day I remember sending a copy to Kpt Lehmann as a xmas present.
https://www.amazon.co.uk/U-boat-evol...809465&sr=8-66