Book Recommendation: Training
It should be "The Cyclist's Training Bible: A Complete Training Guide for the Competitive Road Cyclist" by Joe Friel.

It is considered one of the best books about cycling training, even if you are a mountain biker - endurance training needs to happen on road as you need to maintain reasonable heart rate for lots of training types.

The book has been published several times, the most recent edition in June 18, 2009

After reading it, you can also read Friels blog.