It's a cooking textbook and a cookbook. Unlike a recipe book, it teaches the fundamentals and the theory along with the recipe. It's the one text almost every professional and serious hobbyist has on the shelf or, more likely, in the kitchen covered with stains. A reference book.
If I had the time, I would take some serious cooking classes because I love to do justice to the earth's bounty. I know Mrs. BD and I would enjoy one of those 5-day courses in Amalfi or Florence. Or better yet, in some village in France. French country food is the best.