I am sure that there were many topics about this guy already. But I want to concentrate on this book, which, for some reason is not his most popular book and it's quite hard to find it. Anyway it's definetely his best book that was written for martial artists.
A few points
1. It's not for boxers only. In fact it's a valuable book for anyone who practices striking martial arts (esp. kickboxing and thai-boxing).
2. It's mostly about how to prepare physically (and mentally) for a fight. There's everything - shitload of exercises, sample routines, lots of information about nutrition and much more.
3. It will be a good read even for those who are not interested in martial arts (but just want to keep fit).

Here's more info on that book:
http://sfuk.tripod.com/reviews/enamait_boxguide.html

Here is Enamait website:
http://www.rossboxing.com

Apparently he's discontinued these books because they're superceded by his new ones, which are much better. II, NG and FTC are way better in my opinion ( although I'm still waiting for my copy of FTC to arrive ).