Peter's Books are very good indeed. I enjoyed "Bonsai Design - Japanese Maples" very much, and is probably one of, if not the best indepth guide to growing them.
I've been looking out for the other Bonsai Design series of his books, but have been unsuccessful sourcing them at my local library. Its a shame that his books aren't republished, as some retail at over $250 on some sites, which is way out of most peoples price range. I've seen his book "Japanese Maples" sell over £90 on ebay.co.uk.
Try your local library if not, get saving those pennies
All the best,
Aaron