The textbook consists of chapters devoted to paleography (the science of manuscripts), heraldry (the science of coats of arms), sphragistics (the science of seals), chronology (the science of the time counting system), metrology (the science of measuring distances, weight, volume) , genealogy (the science of the origin of clans), etc. These sciences are united by the concept of “auxiliary historical disciplines”, since without them it is impossible to study and understand the past. The book reveals the features of the methodological techniques of each of the disciplines, the specifics of the subject. The main thing is to help the student comprehensively study the historical source and give maximum information about its origin.