The book examines and confirms the hypothesis that differences of regional order are typical for the Armenian medieval culture of khachkars: a favorite theme, motive or system of practical techniques created by the accumulated experience of local masters, which was passed down from generation to generation and which ultimately defines the concept of "art school of khachkars." After studying khachkars of the 9-17th centuries. in Aragatsotna and Kotayka, it became obvious that at the early stages of the development of the culture of khachkars - in the 9-11th centuries. and during its sunset - in the 16-17th centuries, the architectural forms and artistic compositions of these khachkars are everywhere similar. However, in the period from the end of the 12th century. and until the end of the 15th century. khachkars acquire a pronounced originality of composition, depending on the place where they are installed. The book is intended for medieval historians, as well as for a wide range of readers.