If you play AD&D, and do not buy this book the second you see it, you are in a world of trouble friend. TSR almost REQUIRES use of this book in the newer campaign settings. And why not it is a very good book, with interesting new spells and spell schools. The only reason I gave this book such a low score it because first off, you really NEED this book to play AD&D well. Which brings the grand total of books you need to play AD&D with upto 4. (Players Handbook, Dungeon Masters Guide, Monster Mannual, and now this). Secondly the new and improved Players Handbook should have included this in it to cut costs.