I have bought many of Andrew's books and illusiontech is great for people just starting out, or if you have been building illusions for a while. But I would also recommend the illusion impact series he has out .
I own tarbell 1-8 all are worth it, just buy the book but this is a DVD on it at this link: http://www.penguinmagic.com/specialorderproduct.php?ID=8523