The problem with the documentation isn't that it's difficult to grasp, but that it's scattered all over the internet, i.e. some useful stuff is on stackoverflow, some in blogs, some in official documentation. It's a good niche for a book, i.e. many people would buy it, provided, that it has a comfortable price.

I like the book and contents, but the price on the site is quite large. A can buy a bunch of tech books on IT ebook sites like Oreilly's for it. I would buy it without thinking for $10, with some thinking for $20, and for something around $30, I will buy only after thinking through about whether I really need it.