"Twist of the Wrist II" by Keith Code, and "Total Control" by Lee Parks are both excellent books, and both are sold by Amazon.
How do I know this?
I ordered them both from Amazon.com at the same time a few weeks ago and got free shipping and discounted prices, total was around 30-some US$.
I have already read Code's book and am now reading my way through "TC".
Definitely an investment the serious rider should make...