If we speak in a dry and strict language, it should be said that the book is devoted to the doctrine of the solid, liquid and gaseous state of matter .. However, a feature of this popular work is that structural problems are considered from a certain angle, namely as manifestations of a kind of struggle of order and disorder in the world of atoms. At the same time, the author managed not only to lay out the foundations of the theory of the atomic structure of substances, but also to consider many important technical processes. The book is written in simple language and is designed for a reader familiar only with the basics of physics.