NONFICTION: "The American Way of Eating," by Tracie McMillan

If you've given any thought to how food finds its way to your mouth, you won't be surprised by Tracie McMillan's undercover reporting.

But these pages will leave you with vivid, challenging images of how food is harvested, sold and prepared (loosely speaking) at casual restaurants. You may, like the author, reel from the heat of California's Central Valley farm fields. Your nose may wrinkle, too, at the aromas of rot just a swinging door away from the lovely produce displays at Wal-Mart, which now sells more than a quarter of America's groceries. And the next time you're at Applebee's (or Chili's, or TGI Friday, or any of those a-notch-above-fast-food spots), you may remember that everything on your plate is portioned from plastic bags, that "cooks" in the back do nothing more than assemble calories to look appealing.

McMillan, an award-winning journalist whose career focuses on food and poverty, invested a full year working in the nation's food trenches, posing as a troubled young woman who needed pay, any pay.

She also lived off her undercover income -- precariously, at times. Some of her most touching stories involve food-related generosity from others no better off than herself.

When you work from a concept like hers, pretending you're "one of them," you get from your day's labors only what you get. This book includes only a small handful of "gotcha" moments (as when a Wal-Mart co-worker reveals that baking potatoes sold wrapped in plastic are merely washed, not scrubbed). But McMillan pumps up her sometimes tepid narrative with solidly reported insights into the often sad, unjust, corrupt, greed-driven path of food in modern America. She also touches on some optimistic experiments with, for example, urban agriculture. Footnotes appear on many pages, and fill 38 pages at the back.

What others have called "the paradox of plenty" is evident. "Put simply," she writes, "our agriculture is abundant but healthy diets are not."

In its final chapter, this book proposes changes. Why not coupons for fresh produce, not just stuff in boxes and cans? Why not publicly funded cooking classes so the masses know what to do with fennel and eggplant? Why not a publicly funded food distribution network that would guarantee access to healthy calories for every American long guaranteed access to electricity?

How did her undercover year change her? She told me by e-mail that she rarely eats out anymore. She is glad for government regulations, having learned at Applebee's and Wal-Mart that food safety laws are followed not for goodness' sake, but for fear of fines. Mostly, she said, she is more aware of and grateful for the "literally thousands of people in the world working to feed me."

They're often ill-paid, and can't afford to eat healthfully themselves, but they keep our economic engine stoked and happy -- though not healthy enough.

Susan Ager is at susan@susanager.com.