(I need to finish writing this page. Just skip ahead to the next section, OK?)
People often ask me to recommend cookbooks. My experience is that any cookbook which starts "from scratch" instead of using prepared ingredients can be useful. One that I particularly like is Julia Child's The Way to Cook. Rather than give individual recipes in great detail, this book gives examples and then points out substitutions and variations on the theme. For example, there's a discussion of broiling fish which mentions a dozen different kinds of fish you can prepare this way. If you try a few different things, you gain some understanding of what you're doing instead of just following directions.
For much more basic recipes, but still avoiding a lot of prepared foods as ingredients, you should look at the old standbys: Rombauer's The Joy of Cooking and The Fannie Farmer Cookbook. If you can find an old Fannie Farmer it's even better, because most modern prepared foods weren't around yet. I've got a 1920's edition that my wife inherited from elderly neighbors. You can buy a reprint of the 1896 edition (or any other cookbook I mention here) at amazon.com.
When birthdays come around, you'll be glad to have Rosie's Bakery All Butter Fresh Cream Sugar Packed No Holds Barred Baking Book by Judy Rosenberg. (Since standard baking powder and confectioner's sugar both have cornstarch, there's no use looking in bakeries for a corn-free cake.) I've baked my own birthday cake the last few years using this book and last year a professional chef asked me for the recipe! It was the high point of my baking career.