My home library is stuffed with cheese books. (You’re surprised?) I have cheese books that make me hungry and dry dairy-science textbooks that don’t. I have cheese cookbooks, encyclopedias, compendiums and memoirs. I have cheese books in four languages. But I don’t have any cheese books as smart, provocative and well written as the new Reinventing the Wheel: Milk, Microbes, and the Fight for Real Cheese by Bronwen Percival and Francis Percival.

The Percivals, who are married, have spent the last several years exploring the factors that produce distinctive cheese. They aren’t scientists. Bronwen, raised on a California dairy farm, is the London-based cheese buyer for Neal’s Yard Dairy, the esteemed retailer and exporter of fine British cheese. Francis has won several big-deal awards for his wine writing. But they are skeptics and keen observers, convinced that “progress” is no friend to cheese. Cows bred to produce more milk and creameries scrubbed clean of microbes aren’t the path to greatness, they argue. Milk is—but raw milk that reflects the farmer’s practices and landscape, not the “microbial blank slate” that pasteurized milk represents.

Kirkham’s Lancashire, pictured above, was the only cheese the couple served at their wedding. Francis’s parents are from Lancashire, but more significantly, this handmade cheese represents an approach to cheese making that Francis and Bronwen  admire, by a cheesemaker who responds to each day’s curd, not to the clock. “It’s a vestige of another era,” writes Francis of Kirkham’s Lancashire.

Some readers may come away from this book believing that the Percivals are dismissive of science. But Francis insists that the reverse is true. Cutting-edge technology like DNA sequencing allows cheesemakers to decipher the complex microbial world on their cheese rinds. But what these contemporary techniques are revealing is that our great-grandparents knew best. The raw milk they used had flavor and enough good bacteria to outcompete pathogens. And they didn’t have to rely on purchased cultures, with their predictable aromas and flavors, to get their milk to ferment.

“Only now are we beginning to appreciate the collateral damage caused by the out-and-out war on milk bacteria over the past thirty years,” wrote the Percivals. The loss of diversity is noticeable and troubling; when cheeses are made with “clean” milk and a limited range of laboratory cultures, they taste the same.

There is so much wisdom and sanity in this book, expressed in admirably vivid prose. Every great cheese is unique, capturing what the Percivals call the flavor of the farm, not the flavor of the process. “More than anything else,” Francis told me by e-mail, “we are arguing to avoid sameness.”