For the 150th anniversary of the birth of Johannes Brahms (the actual date is May 7), the Library of Congress is holding a festival that continues through Sunday morning with panels, lectures and performances as well as a display of manuscripts.

Participants include some of the world's leading Brahms scholars and performers, and there were even two world premieres on the opening night, Tuesday -- small, youthful piano pieces that the highly self-critical composer neglected to burn.

The Library's display drawn from its remarkable manuscript collection is as impressive as the music: 19 items in Brahms' handwriting, including such major scores as the Third Symphony, the German Requiem and the Violin Concerto. The Concerto is particularly interesting because it was composed in consultation with Joachim, the composer's violinist friend to whom it is dedicated. The revisions at various times were done in different-colored inks, making it easy to compare the first and second thoughts of this very thoughtful composer. Those who are fascinated by the part of the manuscript that can be read in its display case may want to browse further in the handsome edition published by the Library, which faithfully reproduces all the colors.

Remaining events of the festival: FRIDAY -- 9 a.m., conference on Brahms theory; 1:45, conference on Brahms' symphonic music; 7, lecture entitled "Brahms: Songs With Words and Songs Without Words"; 8:15, concert featuring Detlef Kraus, piano, Paul Sperry, tenor, Irma Vallecillo, piano, Cantilena Chamber Players. SATURDAY -- 9 a.m., conference on Brahms and early music; 1:15, conference on Brahms as editor; 4, founding meeting of the American Brahms Society; 7, lecture on Brahms the Romantic; 8:15, concert featuring Charles Rosen, piano, Robert Gerle, violin, Richard Todd, French horn, Concerto Soloists of Philadelphia. SUNDAY -- 9 a.m.: conference on Brahms as song composer.