Just recently I've been asked many times for what books out there are good for training. Here is a list of my favorites. I tend to keep away from the coaching books as I have a coach and don't need training programs or advice. I like to find books that help me understand the scientific and researched aspects of swimming, cycling, and running so that I am not reading some coach's opinion, but rather facts that have been vetted through scientific methods. Here they are:
Breakthrough Swimming by Cecil Colwin - history of swimming and how it evolved to the strokes used today. Contains lots of research as well.
Swimming Fastest by Ernest W. Maglischo - lots of science in here - a huge, thick book. Great stuff and the latest on training techniques.
Lore of Running by Tim Noakes - much research into the science of running.
Pose Method of Running by Dr. Nicholas Romanov - training to run on the balls of your feet, much MUCH easier on the knees!
Serious Cycling by Ed Burke - lots of great research into the science of cycling.
Workouts in a Binder by Gale Bernhardt and Nick Hansen - great waterproof workout book to take to the pool and do your own workouts. Workouts range in distance from about 1500m to about 4000m, with the bulk being in mid-2000s to 3000s.
Workouts in a Binder for Swimmers, Triathletes, and Coaches by Eric Hansen - like the previous, but only with significantly longer workouts into the 4000s and 5000m range. Great for Ironman training!
Training and Racing with a Power Meter by Andrew Coggan - ever since I bought a computrainer and then a PowerTap, I've been sold on power training. This book nicely explains it all in one place.