The author focuses on the enormous contribution made by Yury N. Stolyarov to the development of the methodology of modern bibliology, discusses the basic provisions of Stolyarov’s document theory as applied to the studies of special bibliological problems. The author substantiates the priority of documentological approach to the study of the concept of the book, based on the method “from the abstract to the concrete”, which was used by Yu. N. Stolyarov to study the document. The author also argues that this approach enables to consider the book as a component of the comprehensive documentive system and to identify the trends in its development in the digital environment. She also defines the terms of “substantial document” and “functional document”, introduced by Stolyarov to develop the book typology. The contribution of Yu. N. Stolyarov’s works to the system characterization of the book as an object of communication, as well as to the development of problems of book culture and the culture of the book, is emphasized. The author concludes that the fundamental studies in documentology by Yu. N. Stolyarov have laid the foundation for modern bibliology and are highly relevant, in particular for training future librarians and publishers, as they provide the comprehensive understanding of the book and its status in the structure of the document.