Are there books describing the general principles of cooking? Perhaps my question is too weird, but whenever I read a book on cooking, it's just a list full of recipes. There are a lot of examples but there are no explicit laws or general principles of cooking  - here I must admit that I don't browse this kind of books often, so perhaps this is pretty common and I still didn't have the luck to find them. 

In the cooking books I've looked, as I said earlier, there are a lot of examples. So one must practice a lot to learn how to improvise or change or invent. I'd like to know about principles from scratch - examples are welcome, but the principles are more important than the examples (in my search).
The best resource for this kind of questions is On Food and Cooking: The Science And Lore Of The Kitchen, by Harold McGee. It's best described as 'a cookbook without recipes', even though there are a couple of them in there.

It has several sections and describes in detail what various foodstuffs contain and how they are affected by different cooking methods. For example, there's a chapter on Bread, which goes through the whole process from kneading the dough to the crumb going stale.

It's very thorough, but also very readable. (I have read both the 1984 and 2004 editions cover-to-cover, and I don't think I'm the only one...)