This is an awesome book. But, it is INCREDIBLY detailed and thorough. It took me a few weeks of reading and taking notes and making plans to get through, but I finally felt like I understood triathlon training and planning a training period...be it a week, 6 months or a year.
Before reading this I would get a training plan online, or from a friend, try to personalize it a bit, follow it and do ok. But, after signing up for an Ironman and not wanting to shell out the $$$$$ for a coach to make sure I got through the year injury free and ready to race, I got this book. It's amazing. It goes through planning the year up to your race in great detail....hours per year, per week, training phases for running, swimming, biking, weight lifting, cross training and resting to make sure that you peak at the perfect time for your race. It has workouts, drills, tips...if you learn well from a book, it's almost like having a coach. He has special sections for women, novices, masters, youth and elite racers; injury prevention and treatment, etc.
That said, this book could be incredibly overwhelming if you've never done a multi-sport race or training before, or if you're not into planning/organizing. If you're more the go-out-and-do-it kind of person, this book isn't for you.
However, as someone who struggles with the "Am I Ready?! Can I Really Do This!?" anxiety, especially on race day, this book has very much calmed me down...I know that on the day, I'll be as prepared as possible and ready to go.