I got this book from the library, not Amazon, so I wouldn't feel right reviewing it there. But I think the "critical" reviews on Amazon are generally on point.
For someone who grew up on a dairy farm the subject is interesting. For someone who doesn't cook all the recipes aren't interesting. The coverage is wide and broad, but not deep. He tries to cover milk from a variety of species around the world, tossing in recipes every two or three pages. He wraps up with a brief look at modern US farming. The book started as a magazine article, and it still retains some of that character. The author leans somewhat to the side of organic/locavore dairy, finding farms which are trying to find a niche where they can charge high enough prices to stay in business.
But the author is a bit credulous, I think, in accepting some of the claims. For example, that one Holstein could outproduce 50 Jerseys. Not possible--the farmer must have been pulling his leg.
There's also the claim cows stay in the herd until 3 or 4. Seemed incredible to me--3 means one lactation, which isn't enough to cover the cost of rearing the calf. I know we had cows in our herd aged 9 or 10, because they were still productive milkers. Did some superficial googling and found 4 or 5 is a common figure. Still seems low to me, but then I remembered what we did with our calves: the males went for veal, of course; some of the females we kept and others we sold (depending on whether chance had given us a run of females). The selling is the key--dad could sell calves because there were other dairies in the region, and his herd was respected. Today, I'd assume there's no market for female calves, so they all go into the herd. If the cow has two pregnancies, chances are she's borne her replacement. So the economic calculation for the herd is the cost of rearing the calf until it can be bred and give birth, versus the cow's production over that time. (I'd also assume because of better breeding the calf has a greater potential than its mother had.)