The book was conceived as a presentation, based on the work of the strongest chess players of the past and present, of the modern understanding of the middlegame (middle of the game), the most important stage of a chess game, but went far beyond the scope of this topic. It also talks about the chess game as a whole, and therefore about its other stages; the psychological nuances of chess combat and the role of the human factor in it are shown; Advice is given on how to study theory and how to apply this knowledge in the game. The book is of interest both to highly qualified chess players and coaches, and to amateurs, for whom it can serve as a teaching aid. Theory issues are presented concisely and simply, there are exercises and games for independent analysis, visual diagrams, indicators of strategic and tactical ideas, partners and openings.