Daniels is great.

I didn't believe that marathon-paced runs are not much harder than easy runs. Yet, today, I ran a very scary sounding workout: 4 miles easy followed by 10 miles at marathon pace (6:43/mile), and I wasn't more tired at the end than after last week's 15 miler.

I've grown to like these workouts. They don't hurt, and I like running rather fast rather far.