The premiere last night of George Crumb's "Gnomic Variations" turned pianist Jeffrey Jacob's recital at the National Gallery into a major news event. Crumb, a winner of many honors, including the Pulitzer Prize, stands among the foremost composers currently active in this country. Now in his fifties, he has moved through thickets of trends and countertrends on a highly individual path, using delicately balanced sonorities to convey an intimate, personal world.

This new work is Crumb's first premiere since "A Little Suite for Christmas, A.D. 1979." Also for solo piano, that composition was given here in Washington three years ago. Unlike his previous piano pieces, "Gnomic Variations" contains no amplification, no literary or musical references, and no theatrical effects, which in the past could range from the pianist's singing and whistling to the use of chains and paper upon the strings.

Lasting a little more than 20 minutes, it consists of a theme and 18 variations, which are grouped into three sections of six variations each. It is classic in form and restrained and pure in language. The inside of the piano is used, but these sounds are integrated in a seamless way with traditional keyboard writing. In this music Crumb moves beyond theater to create a masterfully unified statement. Incidentally, he says that "gnomic" refers to the terseness of the writing.

Jacob, for whom the variations were conceived, gave a finely balanced performance, lucidly bringing out the concentrated poetry of the music. He is a pianist of impressive intelligence and sensitivity, as his evocative treatment of the opening Mozart variations indicated. And he has reserves of power which were used with immense artistry in the closing Liszt rhapsody.