The study of personal libraries is important for understanding socio-cultural processes that cannot be assessed by examining other historical events, phenomena and facts. The article deals with the monograph by O.N. Ilyina “Personal Libraries in Russia: Terminology and Historiography” (St. Petersburg, 2022), published in the series “The Book in Russia in the 19th — early 20th Century” by the Russian National Library and the winner of the All-Russian competition of scientific works on library science, bibliography and book studies in the nomination “The best scientific work in the field of library science” in 2023. The structure of the historical and book studies edition, the content of the chapters and the peculiarities of the author’s approach to the coverage of historiography, as well as the stages of the formation of terminology for the study of personal libraries in the domestic humanitarian knowledge in the second half of the 18th — early 21st century are characterized. The emphasis is made on the artificiality of the division of periods in the study of personal libraries in 1917, noted by O.N. Ilyina, because up to the end of the 1920s, book historians, whose professional career began before the October events of 1917, continued to carry out active research activities. This idea is confirmed by contemporary works devoted to the life and work of book historians and bibliographers born in the second half of the 19th century. Special attention is paid to the terminology for describing the history of book collections as a whole (and the collections within them), as well as book marks and marginalia in individual copies. A number of remarks on the design of the reference apparatus of the edition and the rubrication of the text are made, which, however, do not prevent interested readers. The quality, relevance and scientific novelty of the monograph are noted.