I'm not sure I can accurately convey how much I love The Flavor Bible. I finally own it myself, but this is actually the third time I've bought the book. It's probably the best gift I ever gave to my friend Brian, and I got it for another friend last year for Christmas. I will probably end up giving it to everyone I know who cooks eventually. It's that great. It so completely deserves it's name.
It's basically the best aid to improvisational cooking that I've ever seen. The bulk of the book is a massive list of almost every ingredient imaginable, with a brief description of its flavor profile or role in cooking, and a list of other ingredients that make good flavor combinations with the header ingredient. There's a brief introduction at the start of the book that talks about the principles of balance in cooking, and all the different considerations that go into developing a dish, and comments all throughout the book on various ingredients by the chefs who the authors consulted to develop the flavor indexes, but the core of the book is very simple. It's a series of lists.
It's an extremely powerful presentation, and it's very flexible in how you can use it. Brian, for instance, mostly uses it to tweak existing recipes by adding new seasonings. I originally got it for me because he'd mentioned how every so often he gets bored with his own cooking, because he falls into a rut of using the same seasonings over and over again. The Flavor Bible makes it very easy to solve that problem.
I've used it that way myself. Especially with simple dishes, it's very rewarding to look up a few ingredients (say, pasta, olive oil, and eggs) and see what other ingredients lie at the intersection (scallions, as it turns out), and what their main qualities are (the weight of the ingredient, the volume of the flavor, whether it's astringent, piquant, bitter, and so on) I'll often get ideas for several variations at once this way, and they're almost always good. A few more tweaks (shallot instead of garlic, a splash of lemon juice) and it begins to turn into something entirely new.
"Entirely new" is really where it's at for me in using this book. The other night, for instance, all I knew about what I was going to do for dinner was that in flipping through the book I'd noticed that honey was listed as a good combination with scallions. That surprised me, so I wanted to try it. I made a list of other likely ingredients that went with both honey and scallions, and start thinking about what I could make with them, and what else went well with them. I ended up not even using honey (my honey turned out to have crystallized) but the scallion, mushroom, and goat cheese sandwich, on whole grain bread and seasoned with thyme and a fair bit of better, ended up being delicious anyway.
It's made me very aware of how limited my repertoire still is. The vast majority of the cooking that I do is vegetarian and takes place entirely in a frying pan, and much of what I do on a regular basis involves making either pasta sauce (which I'm very good at) or beans and rice. There's a lot of territory to cover there, true, but strangely, becoming more proficient at and getting more tools for improvisational cooking like this has made me more interested in acquiring more traditional cookbooks, and in mastering more recipes from How to Cook Everything. I feel like there's a lot of important information encoded particularly in traditional cultural recipes, and if nothing else, I think mastering a lot of good recipes is going to be the best way for me to gain confidence in my kitchen skills.