what type? just on training in general? supertraining- mel siff high powered plyometrics- james c. radcliffe high performance sports conditioning- bill foran training for speed agility and quickness- lee e. brown, vance A. ferrigno exercise physiology- william d. macardle and ross enamaits books are great... for nutrition.. the paleo diet and the paleo diet for athletes are amazing
For boxing I recommend Boxing's Ten Commandments Essential Training for the Sweet Science by Alan Lachica (for newbies to intermediate fighters)
The Ultimate Boxer by Halbert is the bible of boxing. Written by an olympic coach and only a recent release. Check amazon, highly regarded book.