I'm a few years behind everyone else on this, but I'm finally reading Michael Pollan's The Omnivore's Dilemma. The first section, which is almost entirely about corn (with a bit of beef thrown in), is fascinating. What I particularly love is the portrayal of an entire system that is clearly insane but whose component parts seem entirely rational.
That is, if you're a farmer, it makes perfect sense to plant more and more corn each year (despite how destructive it is to the soil), since potent fertilizer is cheap and you're virtually guaranteed some kind of return on the investment thanks to government intervention. If you raise cattle, it makes perfect sense to feed them corn (despite the fact that they're built to digest grass and that corn causes all sorts of health problems for them) because it's so cheap and because it helps them reach maturity so quickly. If you manufacture soft drinks, it makes sense to use high fructose corn syrup rather than cane sugar because it's so much cheaper. Et cetera. Yet in the aggregate, we have a national agricultural policy that is forcing us to over-produce corn and then to figure out what to do with all the excess biomass. So we work more and more corn into our diets and into the diets of the animals we eat.
Individually rational, collectively bonkers.