Edit: Anyone interested in learning to cook, Americas Test Kitchen Cooking School (And also Cooks Illustrated Cooking Science and Science of Good Cooking) would probably be good for much of HN's audience. It is much more of a cooking "textbook" than most cookbooks. It explains what you are doing and why you do it instead of just a big list of recipes. There is also Modernist Cuisine but those are really pricey.
For general cooking, I will also recommend La Technique [2], its short and digestible (puns always intended) increments of learning that, while old, are fundamental and classic.
If you can work through La Technique and something like Julia Child's Mastering the Art of French Cooking [3] (Which is great, but, very dense) you could move on to (and invest in -- they really are expensive) Modernist Cuisine [4], for which I think you need a good basic education on the fundamental building blocks of cooking.
[1] https://www.amazon.com/dp/B00F8H0FNW
[2] https://www.amazon.com/dp/0812906101
We've got copies here in the Seattle system.
I've been looking for stuff like this after reading "Cooking Comics" (by Lauren Thompson (Author) and Tsukuru Anderson (Illustrator)). It's a graphic novel/comic book but what's nice about it (beyond being aimed at beginners) is that they have this nice, systematic approach.
Start with stock, talk about why it's important and how it's done, move on to soups, demonstrate two types of soups, etc, etc. Each one has a simple recipe (and the ones I used worked well)
After reading it I'm totally jazzed about a 'cooking school textbook' sort of approach :)
I'm ordering the Cooking School book as we speak. I'm currently trying to teach the bf how to cook and this seems like the perfect tool to go through.
Another recommendation I'd make for improvisational cooks/bakers is The Flavor Bible. It's great for "what do I do with these random ingredients in the fridge"?