You will find yourself looking up just about everything in this book, and you will be surprised at some of the incredibly useful information you find. If you want to know what's in your shampoo/soap/lotion/toothpaste/vitamins/etc... whether it's good or bad for you, and what it was derived from, this is your book. You will probably find yourself wanting to buy a copy for everyone you know with allergies or sensitive skin. I started with the 3rd edition and I must note that the revised version is loaded with additional information. If you own one of the earlier versions it's worth the upgrade.