This slim volume is a reprint of the U.S. Navy translation of a captured German submarine commander's manual. This edition includes a number of photographs, mostly of U-505 shortly after it was captured by Rear-Admiral (then Captain) Daniel V. Gallery's hunter/killer group in 1944.
The handbook is a very basic volume, but gives a good overview of tactics, approach and evasion techniques, and so forth. Like most naval publications intended for commanding officers it presumes the reader possesses a good deal of basic knowledge. It was, after all, written for officers who had already completed submarine school, and served in u-boats long enough in subordinate positions to qualify for command. Consequently, you don't get some of the detailed instructions you might wish to have.
For example, some basic instruction is given on determining target range based on masthead height and angle of view as determined by comparison to the markings in the periscope optics. But it presumes that whoever is doing this already knows how to read those markings. For those with the knowledge, this section also gives an indication that German periscope designs were less advanced than those in American submarines. German periscopes could only be used for estimating range on the low power setting, and that had to be calculated manually.
Despite these possible shortcomings, this book remains a valuable reference. It gives a good overview of how to fight a u-boat, as well as some idea of how the Germans perceived Allied anti-submarine capabilities. "...we can assume that it is similar to [the capabilities] of our own sound locating instruments." (In fact, close to the end of the war, the Germans had by far the superior equipment, but this is one of those areas where prudence suggests it is always wiser to err on the side of caution.)
One of the things this book does not mention is the possibility that the Allies were intercepting radio traffic between headquarters ashore and the boats, which, in fact, they were, accounting for a very high percentage of kills. This was simply something that the German command didn’t know, and didn’t become aware of until many years after the war had ended. The Allies were very careful to give the impression that they were finding the boats by using their own admittedly more advanced radar, and not because the Germans were unwittingly telling them where they would be.
All in all, this is a good basic reference, and should probably be in every u-boat enthusiast's library.
NOTE: Review refers to a different edition. While the translation is the same, the linked edition has different photographs and other additional material, much of it from German, rather than American archival sources.