Leonard Bernstein's charisma as a conductor tends to obscure his reputation as a composer. Even when we do think of him as a creator, it's his musicals, such as West Side Story, that come to mind first. Yet he was as serious and prolific a composer of concert music as he was of dramatic works. Leonard Slatkin's programme with the BBC Symphony Orchestra gave us a rare chance to hear Bernstein's Second Symphony, "The Age of Anxiety".

The piece is based on WH Auden's monumental poem of the same name, written as a reaction to the devastation of postwar Europe. Bernstein's 1949 symphony restages the poem's epic conflicts as a drama of differing styles and compositional approaches. The work's diversity is signalled by the contrast between a solo piano part - here lucidly performed by James Tocco - and the orchestra.

The Dirge, Masque and Epilogue contain the most powerful music. The funereal tread of the Dirge is based on a theme that uses all 12 notes of the chromatic scale. First played on the solo piano, the theme becomes an orchestral scream at the climax. It's as if Bernstein sees the sterility of 12-note serialism and abstraction as a kind of spiritual death. Out of the embers of this elegy appears a ghostly jazz riff, which becomes a riotous jam for the pianist and the percussion section. The Epilogue, based on a radiant string theme, closes the work on a note of apparent optimism.

What is moving about this symphonic kaleidoscope is the way Bernstein does not resolve the tensions between its disparate elements. Tocco, Slatkin and the orchestra were alive to the music's seething diversity, and were as convincing in its moments of out-and-out jazz as in its passages of Mahlerian gloom.

There was eclecticism of a less rich kind in Christopher Rouse's percussion concerto Der gerettete Alberich, here played by Colin Currie. The work is a camp drama that imagines what might have happened to Alberich after the end of Wagner's Ring. There was no doubting Currie's energy and enthusiasm, but even he could not save the work from sounding overblown and empty.

· Slatkin and the BBCSO play two Bernstein symphonies at the Barbican, London EC2 (020-7638 8891), tonight.