All About Thickness
All About Thickness, by Ishida Yoshio, pub. Ishi Press (G34), 1990. Now out of print.
I had never heard of this book until a friend from the Go club insisted that I borrow and read it. It's quick and very useful. Each chapter is four pages, each with a full-size diagram plus drawn and written commentary.
By using the whole board instead of smaller foci, the author does a great job of demonstrating how groups can work together to use influence most effectively (and how to get in the way of same when your opponent tries to make territory). Some of the chapters are less useful ("Kaizen's Great Masterpiece"), but interesting nonetheless.
Entertaining and enlightening, as a good Go book should be.
-- Scartol
See also David Carlton's review.