Sergey Sergeyev-Tsensky loved books and collected them throughout his life. Above all, he owed his encyclopedic knowledge and erudition to books. His library houses a lot of books on the history of Russia and the Crimean War of 1853–1856.

The displayed bookcase contains two significant encyclopedic editions of the end of the 19th century — the first half of the 20th century, and those are the Brockhaus and Efron Encyclopedic Dictionary (the volumes published between 1890 and 1904) and the first edition of the Great Soviet Encyclopedia (the volumes published between 1926 and 1947).

The Brockhaus and Efron Encyclopedic Dictionary was initially planned as a translation of the German dictionary published by Friedrich Arnold Brockhaus. The first eight volumes are virtually word-for-word translations, with minor additional explanations provided for Russian-speaking readers. Starting from the ninth volume, the edition stopped relying on the translated material and began to feature new articles. Many prominent scientists and philosophers of the time were invited to join the editorial board, including Dmitry Mendeleyev, Vladimir Solovyov, Semyon Vengerov, Andrey Beketov, and Alexander Voyeykov. Also, there were two versions of the dictionary. The first one was considered somewhat of a deluxe edition and consisted of 41 volumes, whereas the second, a more modest-looking one, included 82 half-volumes.

The idea of publishing the Great Soviet Encyclopedia was offered by Academician Otto Schmidt in 1923. Over just 21 years, 65 volumes and one additional volume were published.

The editorial office of the Encyclopedia was located in Moscow, in the former Annenkov house on the corner of Petrovka Street and Kuznetsky Most Street. The feature editors and authors of long articles included leading Soviet scientists and statesmen: Nikolay Burdenko, Nikolay Bukharin, Kliment Voroshilov, Igor Grabar, Ivan Gubkin, Gleb Krzhizhanovsky, Lev Kritsman, Valerian Kuybyshev, Vasily Williams, Mikhail Nesturkh, Nikolay Kun, Yury Larin, Anatoly Lunacharsky, Nikolay Mescheryakov, Vladimir Milyutin, Vladimir Obruchev, Yevgeny Preobrazhensky, Karl Radek, Nikolay Semashko, Ivan Stepanov-Skvortsov, Mikhail Frunze, Pavel Florensky and others.