The author pays tribute to late Mikhail Nikolaevich Glzkov, a well-known library historian. He reviews the main stages of Glazkov’s life and professional career, analyzes his approaches to the studies of document historical content. The author acknowledges the scholarly soundness of Glazkov’s texts, deep knowledge of archival sources, color and alertness in his writing. Many of his works focus on obscure and understudied problems of the national library history, as well as on the topics related to the most controversial historical periods. The author places special emphasis on the fact that Mikhail Glzkov was the disciple of Konstantin I. Abramov, Russian prominent historian of librarianship. The author concludes on significant contribution made by Glazkov to the national library historical studies.