Chris McDougall's Born to Run has a simple premise: homo sapiens are on the top of the food chain because before we developed tools such as spears, atlatls, bow and arrows, we ran our food to death. As the title indicates, homo sapiens whooped the Neanderthals because what we gave up in top speed and strength, we gained in endurance. We did this by gaining specific advantages of running animals: Achilles tendons, a nuchal ligament to control our head movement, our ability to dump massive amounts of heat through sweating (unlike our furry prey), and our ability to disconnect our breathing from our stride. And butt muscles.
All of this takes place with the background of the Tarahumara people of Mexico competing in the Leadville 100 in 1994 and a 50 mile race on their home turf against the world's best ultramarathoners. These people are the best runners in the world, and have shown that running is the fountain of youth. Their culture lacks illnesses that attack modern societies: diabetes, heart disease, clinical depression, cancer, etc. And they don't get injured running all those miles. Which leads us to theme number three. And their diet lacks all the processed foods of modern society.
Born to Run also attacks Nike and every other shoe company out there. Modern running injuries didn't exist because people ran in thin shoes. Feet are meant to take a beating. The nerves in the feet are similar to those in your hands, face and genitals read: sensitive. They are constantly trying to find a hard place to land on because the foot is an arch. It gets stronger the more force push down on it. However, support an arch from underneath (like with a modern running shoe), and the arch collapses.
To summarize the argument, Nike created a market for a product and then created the product. And when the market needed shoes to correct the problems and injuries the market created, (read: over/under pronation, shin splints, etc.) Nike and co. created shoes to fit the market. And so on.
The upshot of this is that I am running in my racing flats and have been for about two weeks. My feet feel stronger, particularly in my toes. I am striking midfoot instead of on my heel. The only problems is that the shoes are not designed for Minnesota winters.