This is a first hand personal history of a famous WW2 U-Boat commander, the only one to survive service from the early war years. Cremer provides a candid, readable record of his service, from his time as an officer on destroyers in Norway, his transfer to U-Boats summer 1940, and successful cruises followed progressively more fruitless campaigns. It concludes with a brief command of a new revolutionary XXI boat, it's loss, and his command of Großadmiral Dönitz's personal guard in May 1945.
The author provides a valuable account of increasing technological inequities encountered through the years (increased certainty of detection and destruction), and later cruises without kills but replete only in narrow escapes.
The edition I read (Naval Institute Press, Cloth Bound, 1985) includes a an appendix ("German U-Boat Casualties in WW2") that lists the fate of each U-Boat in service: it's a staggering tabulation of `heroism' and/or suicidal persuasion.