I’m going to give you my top three cookbooks for any cook’s shelves.
I learned a lot about food from watching Good Eats. Alton Brown is a good teacher. I’m Just Here for the Food is a great resource if you know nothing about cooking. Alton Brown will break down everything from cuts of meat to how to choose an appropriate cooking method. While there are recipes, this is more like a cooking manual. If you have no idea what you’re doing, this can be your cooking basics class.
The Joy of Cooking is a long time kitchen staple. The recipes are good, and each major section includes some technical instruction. I recommend finding a copy of the 75th Anniversary edition if you can. It includes some more unusual recipes for this day and age. If you need a solid basic recipe for just about anything, Joy of Cooking probably has it.
If you want to learn to be an inventive cook, this is the one book you need. It is an encyclopedia of which flavors go with each others. Want to know what goes well with beets? Turn to the entry for “beets” and get the full list of recommended flavor combinations. While the entries are very good, sometimes an ingredient isn’t cross-referenced in both directions. That flaw aside, I highly recommend this to an aspiring cook.
With those three books, you can figure out how to cook nearly anything. (Baking is another story though Joy of Cooking will give you a start there.)