This is a history book on Japan, but an old one, from 1994, so misses the point on speaking about the Japan of today. It's also a very criticized book, mainly because "it gives you the wrong idea on how the japanese people are". But the author starts saying that this is the underground Japan, and that he didn't knew that part of Japan until he started looking for it, so I think the book is fair.
As a person interested in knowing the most about Japan, and since I know most of the general part of Japan history by now, this was a great way to get to know a small part of japanese culture. Several subcultures, to be exact. And I guess the author did a good job in discribing it, it felt credible. It's also written in a story-like way, so that it doesn't get boring.
If you want to know the underground subcultures of Japan, this is a great place to start. And you know, you end up getting a lot of knowledge about the general culture in the context, so, it's also a nice book to learn sometime about the japanese real culture.