It is hard to imagine classical music without Johannes Brahms. After Beethoven seemingly exhausted all that there was to say in traditional musical forms, Brahms arrived and injected a fresh combination of intelligence and expressiveness. The composer's four symphonies, two piano concertos and choral masterwork "Ein deutsches Requiem" are beloved concert warhorses, while his smaller-scale works are pillars of the chamber music repertoire. Brahms's way of merging flowing melodies, rich harmonies and genuine expression caters at once to the heart and the mind.

With its season winding down, the National Symphony Orchestra broke away from its usual format and presented an engaging portrait of this central musical figure. After a polished multimedia lecture on Brahms's life and work that included musical examples played by the orchestra, Music Director Leonard Slatkin led the NSO through a blazing performance of Brahms's Symphony No. 1 in C Minor, Op. 68. At each turn, the performers smartly elucidated Brahms's genius.

The narrator for the discussion was Martin Goldsmith, the classical music programmer for XM Satellite Radio and the author of "The Inextinguishable Symphony," a musical biography of his parents' extreme hardship in Nazi Germany. While images of the composer were projected overhead, Goldsmith sketched the broad outlines of Brahms's life, including his early years in Hamburg and his complicated relationship with Clara Schumann. Goldsmith spiced up this wide-ranging narrative with many of the composer's funny quips, holding the audience's attention throughout the hour-long presentation.

Among the many musical excerpts, two were clear highlights.

Concertmaster Nurit Bar-Josef and pianist Lambert Orkis brought mature musicianship and superb technique to their lustrous and all-too-brief solos in the composer's Violin Concerto in D, Op. 77, and the Piano Concerto No. 2 in B-flat, Op. 83. Slatkin played up the tension and stress of Symphony No. 1, highlighting the conflicting material, incessant drumbeat and searing strings of the strong introduction. Fueled by the forward press of the darker forces of the orchestra, the ensuing material culminated in several grand outbursts.

There were no moments more utterly Brahmsian than the central movements where the composer stops the fist-shaking and shows his sunnier side. The second-movement andante pulsed with emotion as the musicians welled up rich pools of sound. The delightful scherzo was sinuous and gentle. Bar-Josef, oboist Rudolph Vrbsky and clarinetist Loren Kitt offered shapely solos, intelligently rising above and folding back into the busy textures as necessary.

The finale was all mystery and fire, with Slatkin patiently bringing together the contrasting themes. Here were soul-stirring strings carrying a triumphant theme; there were the grand chorales that bring this masterwork to a close. The NSO brass resounded with stentorian power in the glorious closing measures.

The NSO's pleasing portrait of Brahms repeats tonight and tomorrow evening.