The first theme of Slava! is a vaudevillian razz-ma-tazz tune filled with side-slipping modulations and sliding trombones. The second theme is a canon, and after a brief development section, the two themes recur in reverse order. Near the end, they are combined with a quotation (proclaimed by the ubiquitous trombones) from the Coronation Scene of Moussorgsky's "Boris Goudonov", where the chorus sings the Russian word slava!, meaning, glory!  
In this way, the composer is paying homage to his friend Mistislav Rostropovich, called "Slava" by his friends and to whom the overture is fondly dedicated. The overture was written to celebrate Rostropovich's inauguration as music director of the National Symphony Orchestra in Washington, D.C., in 1977. Leonard Bernstein, the son of a Russian immigrant, was born near Boston, Mass., and studied composition at Harvard. Called "an authentic American hero, an arts hero," Bernstein had a distinguished career as composer and conductor. – James Huff