If you don't have time to read the book: read his summary here, this excerpt, or a later essay in which he gives his bottom-line advice: Eat Food, not too much, mostly plants .
After surveying the way food is produced in America, from the mechanized large-scale agriculture of Iowa (which he hates) to the often deceptive marketing of Whole Foods (better, but still suspect), he concludes that small farmers, like Polyface Farms in Swoope, Virginia, are the only true way to grow and eat food. He recommends http://www.eatwild.com as a place to find good local farms (and there are of course many in the Seattle area)
Here are some of my top-of-mind thoughts:
First, I'm sympathetic to the arguments he quotes from Steven Blank, the economist and author of End of Agriculture in the American Portfolio, which argues that from an economy-of-scale and division-of-labor efficiency standpoint, everyone on earth would be better off if Americans left food production to places that have a comparative production advantage over us. If you really care about the world's poor (both here and abroad), you need as much food as possible -- and mass-production is the only way to do that. It's simply not possible to feed 300 million Americans on 50-mile-local food.
Pollan thinks it's good to "Keep your money in the community", or "only trust food from a farmer you can look in the eye". The trouble with these arguments is they're self-contradictory and ultimately have no end. Why is it okay to eat food grown less than 50 miles away, but not 100 or 1000? Maybe I should limit myself just to farmers on Mercer Island? Or for that matter, my own back yard? Pollan himself allows (p. 263) that you can eat non-local goods like chocolate and coffee because people have been trading for thousands of years. Well that's the point: Trade is a good thing, and it is wonderful that today we live in a world that is peaceful enough that we can buy from low-cost and efficient producers anywhere in the world.
There is one extremely good argument for buying locally-produced food, and it's the real reason on Mercer Island I subscribe to Smith Brothers Farms for my milk, and Pioneer Organics for vegetables: it tastes better! Plus, they deliver it to my door! I don't begrudge those who, simply for efficiency reasons , prefer to spend their money and time on more convenient ways of eating (whether at Whole Foods, Safeway, or McDonalds). It takes effort to eat well, and some (most?) people just don't want the trouble.
I get the sense that Pollan and many of the back-to-nature people think economists' obsession with efficiency results in short-term decisions and that if only we could "educate" more people (what are we doing to our environment?! To our children!?), that everyone would revolt if they really understood where that hamburger came from. Well, I say why bother. Once you really taste the produce of a farmer's market, you won't want to go back.