This work belongs to V. Klon, director of the German Akts. О-ва «Frankfurter Maschinenbau Act. Ges.," A great connoisseur of the special field to which the book is devoted. The author managed to develop a very harmonious tolerance building system that can be used in a wide variety of cases. This system is made extremely visual due to the successful introduction of the concept of "tolerance unit"; extremely detailed study of the extremely complex issue of tolerances in screw threads and, by the way, of international threads; it is very interesting to analyze the question of the shaft system and the hole system, which has long been dividing the technicians into two camps, where the author uses a number of examples to find out what structures will come out when using a particular system; the author himself gives an advantage to the hole system, but admits that in some cases it is difficult to do without the shaft system; in view of this, he proposes a means for establishing communication between both systems, consisting in the fact that the main shaft along the shaft system is given a diameter smaller than the nominal one for the tolerance for free movement; the benefits of this are examined in great detail by examples.