Marc Bloom's Run With the Champions: Training Programs and Secrets of America's 50 Greatest Runners is a great book that I've been reading in the past few days.
A couple of quotes that I particularly liked so far were:
"Running has given me so many gifts: courage, responsibility, discipline, motivation - attributes that readily transfer to other of my life. The joy of being physically fit - physically clean, if you will... Even on days when a run starts out with a little struggle, you come home so refreshed." Lynn Jennings in Bloom's Run With the Champions
"To me, running means freedom, but you need the discipline to gain the freedom." Doris Heritage, who ran a 2:02 800m in 1968, in Bloom's Run With the Champions