Captain Dave's Survival Guide

I recently came across a very interesting e-book entitled "Captain Dave's Survival Guide".  What amazes me is that he has the whole thing for available for free on his website.  I have only read a few pages so far, but it easily looks as good as the ones I see advertised everywhere for $20-$40.  Of course, he apparently doesn't spend the money advertising, so I wanted to let people know.