Rodion Shchedrin, probably Russia's best-known contemporary composer of classical music in the world at large, celebrates his 70th birthday on Dec. 16. In honor of that occasion, the music capitals of Europe and the United States have this year given special attention to his music. Shchedrin's native Moscow now joins the celebration with an 11-day festival devoted entirely to his music, which starts Monday with a gala concert in the Bolshoi Theater.

 half features chamber music, with the composer himself at the piano, joined by two outstanding Russian instrumentalists from abroad, cellist David Geringas, first-prize winner at the 1970 Tchaikovsky Competition and, like Shchedrin, a long-time resident of Germany, and violinist Dmitry Sitkovetsky, from the United States.

The Dec. 12 concert brings the State Symphony Orchestra of Russia to the Conservatory's Great Hall, with Sitkovetsky taking on the role of conductor. Soloists include Geringas, Bolshoi soprano Maria Gavrilova and 1998 Tchaikovsky Competition first-prize winner in piano, Denis Matsuyev.

On the program are European premieres of two recent Shchedrin works, the Concerto No. 5 for Piano and Orchestra, which had its world premiere in Los Angeles in 1999, and the "Lolita Suite," symphonic fragments from the opera "Lolita," which was first performed in Stockholm eight years ago.

Other concerts in the festival take place Dec. 4, 5 and 7 in various halls of the Conservatory. More ballet is to be seen on Dec. 8, when the Stanislavsky and Nemirovich-Danchenko Musical Theater presents a special performance of "The Humpbacked Horse," in a version much superior to that of the Bolshoi's revival three seasons ago.

From Moscow, Shchedrin's birthday celebrations move to New York, for the world premiere there Dec. 19 of "The Enchanted Wanderer," an opera intended for performance on the concert stage.

The opening ceremony and concert of the Rodion Shchedrin festival will be held Monday at 7 p.m. at the Bolshoi Theater. 1 Teatralnaya Ploshchad. Metro Teatralnaya. Tel. 250-7317. See events calendar for details on other festival concerts.