| To be fair, I have not seen these. But it's a pretty safe bet that these books mostly cover aspects of his technique. I doubt that it offers a lot of instructional value to develop your ear and help you grow as a player (but again, I do not state that with absolute certainty). Jeff Berlin has often said that just because someone is a smoking player, it doesn't mean they're a smoking teacher. Billy himself has admitted over the years that he knows very little theory. To be sure, he is the best rock soloist out there, but if you're looking to learn about music theory, I'd start elsewhere. | 
