Running - how
McDougall writes early on of being a runner with the personal question of why his feet hurt from running. He then did extensive research and the writing on running here gets into both the technical and conceptual.
In terms of actual how to run advice, there's the ideas of staying below your aerobic threshold and running with a straight back, from the gut and light on the feet. Additional ideas are given around a low meat, low carbohydrate diet (heavy on fruits salads) and using minimalist running shoes.
On this topic, McDougall writes of staying away from new and heavy cushioned running shoes and instead using older broken in shoes. Along these lines, barefoot running or the use of Five-finger shoes is spoken off as definite options that could be worked into. Barefoot running is a fairly controversial idea, but one of the main benefits as trumpeted by it's proponents would be to encourage running light on the feet and help keep the legs under the hips while running. The idea behind beat up or less padded running shoes has the same basis with the striving towards the goal of the natural foot working with you and seeking to find an optimal landing point at each step.
Running - why
McDougall writes both scientifically and through examples from runners themselves of the health benefits of running with it serving to lower disease, help bring about better sleep and serve as an anti-depressant. Additionally, he writes of endurance running as an evolutionary step that our bodies are built for.
Running - how (again)
In terms of conceptual ideas on how to run effectively, McDougall broaches the topic of enjoyment and love of running. Whether it's the Tarahumara, Czech Olympic runner Emil Zatopek or the American runners featured in this book, there's a definite thread of people running well who truly love it. The struggle may certainly be there as people push themselves, but that's enjoyed as part of the overall experience.
Characters in the book
The Tarahumara are the center of this story around running and life, but there's some remarkable Americans featured as well. Early on in the book McDougall introduces Caballo Blanco... the man who came to live among the Tarahumara (and previously went by the names Michael Hickman, Gypsy Cowboy and Micah True). Also central to the story are the ultra marathoners Scott Jurek, Jenn Shelton, Billy Barnett and the iconoclast (though, they all are in one way or another) Barefoot Ted.
Race that ties it all together
There's a lot of interesting content in the book and what keeps it driving forward is the compelling narrative of the Copper Canyon race put together by Caballo Blanco with the Tarahumara and the American ultra marathoners (as well as McDougall himself).
It's fascinating stuff that brings together running (both the how to do it, why to do it and how to feel about it) with the human drama of those competing at the highest level, but with that competition being grounded in a brotherhood of sorts. It's remarkable (and serendipitous at times) content about incredible people and achievements.
Really good book... and in addition to simply reading the the thing, more can be learned about both McDougall and the Tarahumara via a quick YouTube search.