Well, I ordered it! For $10, it's not too bad. I'd call it the Cliff note version of Japanese subs. It is an entry level Navy book. I also own WW1 U-boat and WW2 US sub books in this series. As a collector of Japanese sub books, I felt compelled to buy it. The submarine book by Norman Polmar is much better and in-depth.
It covers the basics of all of the submarine classes, weapons, and tactics. The artwork is the standard Osprey produced drawings. One of the major resorces for the book was
www.combinedfleet.com So, if you want to save the money, just go to the website.
If you're looking for deep analisys, this isn't your book. It is very basic.