I discovered this on the Internet when trying to find something else.
Biogs and Autobiogs of submariners are quite a genre, and one that takes my interest. If you don't like that kind of thing, avoid this book. Of course, nearly all such tales are cast against a military background. The WWII U boat war is heavily rehearsed and is the predominant backdrop.
Cremer describes very well what it was actually like, and reinforces, if it's necessary, just how many German submariners died (nearly all of them - the author was very lucky). He also presents some straight military thinking that I had not read before. But the stand out for me was the section toward the end where he is promoted to join Dönitz' staff, and witnessed the Grand Admiral being "promoted" to replace Hitler as Führer and arranging the unconditional surrender. I imagine a lot of whitewash has been applied.
You have to wonder about a lot of it, though, as keeping diaries was almost certainly a heavily punishable offence.
So I'm happy to add it to the shelf, but it's not as good as Herbert Werner's "Iron Coffins".
Quite an amazing writing on U-boat war from the surviving senior U-boat commander.
The tone is not glory but the hardship, anxiety, and determination. After reading this book, I understand why Das Boot was praised as the greatest submarine movie. What the movie showed could be sensed in Cremer's story. A will to overcome the dangers and still fight on.