Silman's Complete Endgame Course by Jeremy Silman

Jeremy Silman is one of my favourite authors. This book has its material broken down into class and rating so you know how much of the books material to study. There is also a test at the end of each class to make sure you've learned the material. The final part of the book is not for teaching its for everyone to go over and enjoy, endgame's played by the great masters of the past. If you want only one book on endgame's I'd recommend this one.