Virtuoso violinists frequently play excerpts from Bach's Partitas and Sonatas for violin Alone as encores. Seldom are they ambitions enough to plan programs which include he whole set. But Alexander Schneider is doing just that in Sanders Theater under the auspices of Mrs. Elizabeth Sprague Coolidge. He played three last night; tonight he will do the rest.

When you hear a movement from one of these works, the performer generally uses it as a vehicle to show you how accomplished he is. And almost every movement is breath-taking since it requires the violinist to carry two, or (at times) three parts simultancously. But Schneider has resisted the temptation to put himself before the music. As he explains in his program notes, "I believe the most important aim of the performer is to articulate the melodic, harmonic, and contrapuntal lines as clearly as possible, and not to become too involved in the technical difficulties of emphasizing the polyphonic texture alone."

This doesn't mean that Schneider isn't one of the greatest living violinists; he is, and last night's concert proved it. And more than some of his colleagues, he is an honest artist in subordinating himself to his composer.

His performance last night was warm but not Romantic, perfectly intonated, and technically amazing. When the second voice entered in the Fuga of the opening Sonata, a breathless incredulity came over every listener. In the Presto of the Partita in B Minor, his fingers literally clicked over the strings, picking out every sixteenth note, even giving each a slight vibrate. Loveliest of all was the Andante of the last work. Schneider never overdid the sentiment, and the steady beat of the pedal point through the melody held the music to a moving, but ever-calm reserve.

Surprisingly enough, there were empty seats last night, but tonight there is another concert. If you like good music, if you are at all interested in the violin, and if you want to hear one of the finest musicians in the world, don't miss it.