(b St Petersburg, 12 Mar. 1902; d Moscow, 23 Apr. 1978)
Soviet dance writer and librettist. He took private dance lessons in 1918, and began writing dance criticism in 1919. In 1921 he was a founder member of the Young Ballet group (with Balanchine and others). During the 1920s, 1930s, and 1940s he lectured on ballet history in Moscow and Leningrad and in 1937 he worked with Lopukhov in organizing a new choreography department at the Leningrad Ballet School. As a critic he brought a pioneeringly analytic approach to Soviet ballet. He wrote many books of history and criticism, including Didelot (1958) and In Honour of Dance (Moscow, 1968), as well as several ballet librettos, including Sergeyev's Path of Thunder (1957) and Belsky's Coast of Hope (1959).