Prof. SI. Posokhov received a book from his Bulgarian colleagues, which had been eagerly anticipated. This book is a dedication to the exceptional historian and professor of Kharkiv University, Maryn Drinov (1838 – 1906). It was meticulously prepared over several years through the collaborative efforts of Bulgarian and Ukrainian historians. The book encompasses letters and research notes written by Maryn Drinov from 1859 to 1905, spanning an impressive volume of 925 pages. The editors of this significant publication include D. Hristov, L. Solenkova, M. Levkova-Muchynova, P. Bozhinov, V. Ivashchenko, and S. Posokhov. Prof. M.G. Stanchev served as the project coordinator on the Ukrainian side. This book was published at the beginning of 2023 in Sofia by the Publishing House of the National Academy of Sciences "Marin Drinov."