I give this book 9 out of 10 acorns.
I listened to this book a couple years ago and am still ruminating over and sharing bits and bobs from this book. The author painstakingly describes almost every category of produce and what and why certain varieties are more nutritious and delicious than others, which includes, as John mentioned, how to shop for and select the best, most peak plum, carrot, etc. and then how best to store it, and how/when to chop it, and so on.
Partial spoiler alert: chop or mince your garlic ten minutes before you cook it. Read the book to find out why. I love telling people about this little gem of info.
There is an awesome plant / varietal list for gardeners, too.
Eating on The Wild Side: The Missing Link to Optimum Health (Amazon affiliate link).