Puzzles and Studies

Endgame studies and puzzles are extremely valuable. Not too many books have been devoted purely to this area of chess study.

You need three types of endgame books when you study the endgame. You need a book on endgame strategy, covering complex endgames, a book that covers theoretical endgames, as they are the basis without which you cannot hope to understand complex positions, and you need a collection of problems to solve, since that is how you transfer theoretical knowledge into a skill you can apply over the board.