I self-learn many subjects I'm interested in and this book is off to an incredible start.  I just got it today, but I'm so excited to learn everything it offers.  The way it is laid out is engaging and covers the topics enough to make it stick(and cover pesky edge cases) while not boring me and holding my attention.  I have finished a few of the tests and there's no way I could've done it before this book(without cheating).  I will be buying more of these books.