The article presents a three-volume edition of scientific works, manuscripts, books and articles, socio-political notes and diaries, as well as correspondence of Nikolai N. Andreev (1876–1954) – an almost forgotten philosopher, sociologist, revolutionary social democrat, lecturer at Leningrad State University. The collected works include, with few exceptions, almost all of his works: 41 monographs, 80 journal articles and a previously unpublished manuscript heritage, presented to the modern reader more than seven decades after the death of the author. The ideas and materials of Andreev’s creative heritage are based on a materialistic understanding of history, a method of ascent from abstract to concrete, and from this scientific position contribute to the development of problems of Russian philosophy, theoretical sociology, methodological issues of historical science and cultural studies. Andreev’s scientific works contain an understanding and constructive criticism of the methods of building Soviet socialism, as well as his rejection of the unification of philosophical thought in the management system of Soviet society. As an expert observer, Andreev and his publications record an important part of the history of philosophy at Leningrad (since 1991 – Saint Petersburg) State University and in Russia at the end of the 19th – first half of the 20th centuries.