I'm reading this book right now, and it's interesting. It's a training program developed by a couple of guys at Furman University. This gist of it is that your run three key workouts a week, a track workout for speed, a tempo run at race pace, and a long run at slower than race page, and allow at least a day between workouts. The other days of the week you cross train or complete easy runs. The friend of mine who ran a BQ recently trained using this method and improved his PR by about 15 minutes.
There have been some pretty significant improvements for runners all along the spectrum with this program, even sub-3:00 runners have improved by using it. But I did read somewhere that the creators acknowledge if you have more time to devote to running or you are not injury prone, you could most likely do better by running more miles than they prescribe.
Anyway, I'm thinking of training for another marathon with this. It's perfect for people who don't have a ton of time to train, but want to improve. I've never really done speedwork, so it would be a change for me in that regard.
http://www.furman.edu/first/index.htm