I bought this book when training for my first marathon but only got round to reading it after I'd run that marathon. If you want to know more about how to enhance your performance through diet then this book is excellent. It provides information for all runners, of any standard who train at different times of the day. It discusses nutrition through training up to the week of the marathon, the day before, race day & recovery.
Although I appear to have been naturally doing most of the right things, I have already made a few subtle changes and have noticed a difference. Have also picked up some helpful snack ideas which I'd previously not discovered. I'm now hoping to put the theory into practice in preparation for my next marathon.