I hacen't read that one, but I read this book on the mechanics of proper walking and it was helpful. Seem like it probably has similar topics to the above book. Doesn't solve a bad back but does reduce pain somewhat.
Stop Sciatica Now by Pamela Kihm (available from Health Enhancement Resources 400 Main St, 5D, Evanston IL 60202 or
http://www.sciatica-home-treatment.com)
This book is by a Feldenkrais trainer and has exercises to help you sense proper mechanics.