The author of the book, international master Maxim Chetverik, touches on an important aspect of chess theory concerning positional play. In most works on positional play, strategic elements are considered separately, while strategic plans (and, especially, the confrontation of plans) are significantly less common. The works of the classics in this area are not outdated, but a modern view of the problem is useful, taking into account the connection of the middlegame with the current theory of principles.