Each of the sections (a fairly typical selection -- appetizers, soups, fish and shellfish, beef, lamb, etc.) has about 8 to 10 recipes, prefaced by a lengthy introduction about the ingredients at hand and why the recipes were chosen. The recipes themselves are also in narrative style (except for the ingredients, of course) -- and many indeed do include detailed explanations of a key basic cooking technique: how to make a hollandaise sauce or a basic chicken stock, or how to bone a leg of lamb, for example. You also get lessons on shopping for and preparing ingredients, and tips on serving your creations.
But even if you are already a reasonably accomplished chef, I would recommend this book simply for the recipes. I've never made one that wasn't simply delicious. And I really like the mix of best-of-breed classics (his coq au vin and osso bucco, for example) with less common preparations such as his halibut mousse with shrimp sauce (a killer if you want to impress company). Also, while many of the recipes do require a fair amount of time, some are simple enough to prepare after work (the broiled chicken with butter, lemon, soy sauce and garlic is a regular on my weeknight menus).
I'd recommend this book for anyone who likes good food and is willing to put a little time and effort into it. Fields may not be as famous as Julia, Jacques, or Emeril (I believe he died some years ago), but he should be. Also check out All Manner of Food, another of his fine books.
Michael Field's Cooking School will be a welcome surprise for Field fans and a delight for cooks everywhere.