The author discusses the theoretical legacy of Russian bibliography scientist Natalia Andrianovna Slyadneva (1950–2023) through the lens of the contemporary bibliographic theory and practice. She attempts to reveal and promote among the scientific community the ideodocumentоgraphic approach developed by N. Slyadneva in her doctor’s thesis of 1994. The concepts of the ideodocumentographic approach and its value for the bibliographic science for that period are discussed; its theoretical and practical impact on the contemporary information environment is examined. Within the relevant conceptual framework of library and bibliographic sciences, the logics of theoretical construction and the theory key provisions are revealed: Slyadneva’s understanding of bibliography and bibliographic method, specific character of bibliographic object contemplation, hierarchy of sovereign information entities (meanings, text, document, author), and bibliographic information cycle. The author endeavors to explain why the theory has not been implemented in the professional practice and to identify the consequences of rejecting ideographic forms of bibliographic information. The article is based on the author’s private archive.