Smyslov is one of the greatest players who ever lived. His craft as an annotator sets himself in a class maybe all by himself. (How many other writers have held the World Championship?)
Simply put this is one of the best books in my library. I have over 2000 chess books, (not counting pamphlets) and this is easily in the Top 100, maybe even the Top 10.
Want to improve your game? Want to study tactics? Positional chess? Endings? It is all in here, 125 of the best annotated games you will ever see. While Smyslov lacks the ability to touch the lowest rating classes like Chernev, anyone who studies these games carefully could not help but improve. Smyslov here probably spent much more time writing this book than you will ever spend reading it ... and it shows.