I've read plenty of books, most of which were useful. However, they pretty much all say the same thing after a while. Threshold pace is this. VO2 max is that. How to improve economy. etc. Anyway, here's a list of the ones I found useful.
Run Strong
Daniels' Running Formula 2nd ed.
Running to the Top
Better Training for Distance Runners
Lore of Running 4th ed
Road Racing for Serious Runners
Are there any other books out there that can tell me something about distance training worth the $20 that these books haven't already told me?