The Brockhaus and Efron Encyclopedic Dictionary was published in Saint Petersburg, Russia, in 1890–1907 by Brockhaus-Efron, a joint venture of the Saint Petersburg printer I.A. Efron and the F.A. Brockhaus publishing company of Leipzig, Germany. In 86 volumes, the work contains 121,240 articles, 7,800 images, and 235 maps. The encyclopedia was patterned on the famous Brockhaus Enzyklopädie that was published by Brockhaus in Germany in numerous editions during the 19th century, but its contents are distinctively Russian. The encyclopedia was produced under the overall editorship of Professors K.K. Arsen’ev and E.E. Petrushevsky, who were assisted by fellow academics responsible for different editorial departments, such as chemistry, biological sciences, philosophy, geography, philosophy, literature, and music. Many of the articles were written by prominent Russian scholars and cultural figures of the period, including the philosopher, essayist, and poet Vladimir Sergeyevich Solovyov (1853‒1900) and the chemist Dmitri Ivanovich Mendeleyev (1834–1907). Each volume runs to more than 500 pages. The copy of the encyclopedia presented here is a de-accessioned set from the collections of the Library of Congress. The volumes bear the stamp Südostdeutsche Forschungsgemeinschaft Wien (Southeast German Research Association, Vienna), and most likely were acquired by the United States Army after the defeat of Nazi Germany in 1945 and transferred to the Library of Congress. Older stamps indicate that many of the books previously belonged to private or government libraries in Russia.