Courtesy of bitcointalk.org fame.
Sure, the Internet is full of free info but some time it might worth to pay for information, doesn't it? The funny thing is that he only sells it as a DRMed Kindle book, not a DRM-free EPUB at least. Though, I developed some practices so far (not sure if good, but I feel comfortable with them) and I have no idea if the author's worldview is compatible with mine.
One thing for sure: I see so many examples around people complicate bitcoin more necessarily than what it is, got hacked, etc.