You need to read:

Jeff Galloway's "Marathon: You Can Do It!" is one of the best books on running marathons, I've read to date. He takes all that science stuff and makes it readable and enjoyable. It is a must for any of you like me over the 50 year age mark. Just to let you know how easy it is to read...I read it cover to cover in about 5 hours. But I've read most of his other books so I didn't really need to think to much about what he is writing about....that doesn't sound right but...If you read his other stuff...then you don't need to read this. No...go ahead and read this, has a lot more on the run/walk method, and effects of aging.