The proposed book was written according to the program for military schools for the academic year 192728. The author tried to write so popular that the textbook was available for a cadet of the preparatory department of a military school and for a first-year student of a labor faculty. To achieve the necessary accessibility, the author sought both simplicity of language and clarity of presentation. But one of the tasks of adult high school is to prepare the student to read more difficult literature. Given this, the author gradually introduced new concepts into the presentation and, as students enriched with historical information, complicated the material, so that the second half of the book was written somewhat more difficult than the first.