Architectural historian, doctor of architecture (1970). He studied at the Mosk. The VKhUTEMAS (1921-29). Issl. monuments and restoration works in Moscow, Novgorod, Pskov. Tr. Russian architecture of the XI - XIII centuries, Russian architecture of the XIX century wooden architecture, including the book. "The Russian wooden architecture" (1942, with S. Zabello and V. Ivanov), "Pskov" (1950, with V. Lavrov), "History of Russian architecture" (1951 et al.).