Book 1: Encyclopedia of Chess Combinations. Buying the physical book costs around $50-60, but ChessKing has split it into three apps, which used to be $10 each. I bought two copies myself, and now they’re all included in the Maximum package. This is considered the top tactical combination book that can help one become an International Master.
Book 2: Chess Strategy, a master-level middlegame book.
Book 3: Total Chess Endings, an intermediate-level endgame book.
Book 4: Endgame Studies, a master-level endgame book
Once you've studied these four books, you're well on the path to mastery. I’ll prove this through my own practice.