Selecting the ten best chess opening books is impossible since chess players have different playing styles. A positional player might rate an opening book on the Nimzowitsch-Larsen Attack as the best chess opening book, while an attacking player will prefer a book on gambits.
The other challenge in compiling a list of the best chess opening books is the different skill levels of chess players. The opening book that helps you when you are a beginner will differ from that which you find helpful as a strong club player.
These chess opening books are highly rated and cover many playing styles and skill levels.
The Ruy Lopez chess opening has long been seen as white's best chance for an advantage after 1.e4 e5 2.Nf3 Nc6. Many top players and coaches believe your improvement as a chess player depends on your understanding of the Ruy Lopez chess opening.
The Ruy Lopez teaches you a lot about the classical principles of the chess opening, and the Closed Variation, with 9 h3, will deepen your understanding of chess. No matter which side of the Ruy Lopez you find yourself on, you will learn much about chess.
Of course, an opening with as much history as the Ruy Lopez will have acquired a large amount of theory. Do not let this stop you from playing one of the most respected chess openings, but take your time and enjoy every small step towards mastering the opening.