I purchased this as a wedding gift for my second cousin. His grandmother had given me THE JOY OF COOKING for my wedding gift, 23 years ago. The recipes are plentiful and delicious but I use this book for everything. My son came home from school and told me that his nutrition teacher told him that beans and rice do not make a complete protein. We looked it up in the 23 year old book and sure enough there was a section on protein and how humans need the 22 amino acids that make up protein, etc. Then my son needed to work on his Cooking Merit badge for Boy Scouts and was converting Tablespoons to Cups in order to figure out the cost of the meal he prepared. All conversions and substitutes are in there. If you don't have buttermilk and the recipe calls for buttermilk, what do you do? Put a tablespoon of lemon juice or distilled white vinegar in a measuring cup, fill the cup the rest of the way with regular milk to make a cup of "buttermilk". How would I know that?