11 under-appreciated chess books

  1. Textbook of a Chess Game by Richard Reti
  2. I Play Against Pieces by Svetozar Gligoric
  3. Combinational Motives by Blokh
  4. Secrets of Positional Sacrifice by Nikola Nestorovic
  5. Rudolf Spielmann, Master of Invention by Neil McDonald
  6. The Seven Deadly Chess Sins by Jonathan Rowson
  7. Mating the Castled King by Daniel Gormally
  8. Anthology of Chess Combinations by GM Aleksandar Matanovic
  9. White and Black by Alexander Kotov
10. Game Changer by Matthew Sadler and Natasha Regan
11. Chess Gladiator by Asa Hoffman

Good Chess Books for Beginners and Beyond...
https://www.chess.com/blog/RussBell/good-chess-books-for-beginners-and-beyond
https://www.chess.com/blog/RussBell

I'm familiar only with #2 and #3 and agree that they should be better known. Excellent books.

I would add as a candidate for under-appreciated books "Pawn Power in Chess" by Hans Kmoch. Many players dismiss it because it (a) uses odd terminology and (b) is in descriptive notation. Those players are missing out on some of the very best chess instruction ever published. 

I don't know the Kotov book mentioned at the start of the thread but he did write some good stuff. The Middlegame book co-authored with Keres is excellent - often cited as one of the best. His Alekhine biography is also very good, though long out of print. What does have mixed reviews is his Think Like a Grandmaster book and it's two follow ons. They tend to be either loved or hated.