Try the "Joy of Cooking" by Rombauer and Becker. An earlier edition from a junk shop would be even better than the current one.
The authors assume that the reader knows nothing about cooking, and they have organized the book around chapters dealing with basic "how to" - how to pick a cut of meat, how to know when veggies are done, general rules for cake baking, etc. Each chapter on beef, lamb, poultry, veggies, and so forth begins with the general rules on cooking and preparation. They even tell you when it is "safest" to improvise, and there's a whole section on substitutions.
It is my dad's favorite cookbook (he still has his 1936 edition) and mine, too.
Now if I can just keep my husband from peering over my shoulder the whole time :)