I don't recall that my mother had any hardbound cookbooks. There was just her loose-leaf binder and tin box of recipes from family and friends, and some soft cover books she got at the supermarket and so forth. With my mom's help, I learned to bake from one of those, all of which I still have in my collection.
In my senior year in college, one of my roommates had a copy that he brought from home of what I think was the Betty Crocker Cookbook, or maybe it was the BH&G or Good Housekeeping. Whatever it was, we used it quite a bit, and I learned the difference between cloves and cloves of garlic as a result.
But the first cookbook on which my wife and I relied was the 1965 edition of The Settlement Cookbook,
which I believe my MIL gave us when we were married in 1968. It's a treasure of American cookery:
We also had several of the Sunset Cookbooks very early on. We used those a lot, especially the Mexican cookbook -- still some of the best authentic Mexican and early California recipes around, IMHO.
We began collecting soon after we were married and now have more than 1,000 cookbooks.