The beautifully seasoned wood of Sanders Theater affords a sense of dignity, and of majesty. You sit quiet, at one with the sell-out crowd around you: all are mesmerized, transformed if you will, by the beauty of what they hear. On stage, the Beaux Arts Trio performs the world's greatest chamber music, with a virtuosity attainable only by a very few individual musicians, and by no other piano trio in existence.

From the piano bench, Menahem Pressler glances over his shoulder at his two companions, violinist Isidore Cohen and cellist Bernard Greenhouse, each seemingly lost in concentration. Yet the audience hears what the musicians themselves feel: that they are not three performers, but one--one spirit bringing three instruments into unison. Each man is sensitive to the varying moods of his two companions: if one shows signs of interpreting the piece in a special way, the other two pick up on it and follow his lead. "The raising of an eyebrow, the way a phrase is constructed," explains Greenhouse, "can tell us what will come next. Often we are able to understand the ideas going through our colleague's mind even before he does himself."

Such intimate knowledge, of course, comes only as a result of spending a tremendous amount of time rehearsing and performing together. Indeed, the Beaux Arts Trio has been together for quite awhile: this season marks its 25th anniversary. The group was started in 1955 as sort of an experiment among three friends--Greenhouse. Pressler and violinist Daniel Guilet. That first season proved quite surprising: instead of the anticipated eight or so concerts, they wound up playing 80. Upon Guilet's retirement in 1968, Cohen joined the Beaux Arts after ten years as a violinist for the distinguished Julliard String Quartet. Today the group plays over 125 concerts each year, at least half abroad. They are unanimously acclaimed on five continents as chamber music's greatest living piano trio, noted for their vitality and ever-fresh sound. After a quarter-century of play, this freshness shows no sign of waning.

That the music of the Beaux Arts Trio always sounds original and never tired is a tribute to their endless devotion and energy for in the span of over 4000 concerts, they have played every piece in their repertoire many hundreds of times. Still, the trio rehearses before every concert, always listening for new interpretations, discovering new relationships with the music. "Rehearsals are the only time we ever have a divergence of ideas," says Greenhouse. "Occasionally it may get a little tense, especially when one person really tries to push his ideas on the others." On stage, he explains, there is never any tension, only the "amalgamation of ideas." New ideas come during the performances as well, and the musicians are free to investigate them at that moment if they so desire. This gives each concert what Greenhouse "a definite sense of improvisation."

The same freedom of approach to their music applies when the group goes into the recording studio. Here they have distinguished themselves as much as they have onstage. They have turned out an overwhelming amount of material on the Philips label, including the complete trios of Haydn, Beethoven, Mozart, Schubert, Mendelssohn, Brahms, Schumann, and Dvorak. For their efforts, the Beaux Arts have won numerous recording prizes, including the Deutscher Schallplatterpreis, the Grand Prix du Disque, and Gramophone's Record of the Year. The latter was awarded in 1980 for their monumental 14-album set of the complete 43 Haydn piano trios, many of which were previously unavailable to the listening public. Gramophone called this work, eight years in the making, "a landmark in the history of recorded chamber music." Their Silver Anniversary recording of Beethoven's "Archduke" Trio is a current bestseller.

Despite the heavy demands of their concert and recording schedules, as well as their individual solo and teaching careers, Cohen, Greenhouse and Pressler remain the warmest and most personable of men. After their Harvard appearances, which are sponsored by the Winthrop House Music Society, the trio often holds a reception for students at Winthrop. Usually the liveliest people there, they sip coffee, greet fans, and chat with students as naturally and with as much real interest as they demonstrate on stage. As Tom Johnson, director of the Winthrop concert series, puts it, "These guys are incredible! They catch a plane at seven in the morning, travel across country, rehearse, play a concert of incomparable beauty, and do it all again the next day--15 times in a 16-day tour--and still come out smiling! Their energy and vitality simply amaze me."

Johnson first brought the Beaux Arts Trio to Harvard for a single performance in 1978. Celebrating the trio's return to Boston after a seven-year absence, the capacity crowd cheered the musicians as they walked on stage. The following season, the Beaux Arts performed the complete Beethoven trios in a series of three concerts in Sanders Theater. The series sold out in advance by subscription. For this their anniversary season. Winthrop House scheduled four Beaux Arts concerts: the fourth happens tonight. Once again, the concerts sold out by subscription last fall in a matter of weeks.

For those not fortunate enough to own series tickets, the Beaux Arts Trio is also offering fifth, non-subscription, concert tomorrow evening, for which tickets are still available. The program, which is the same for both tonight's and tomorrow's concerts, is perhaps the most exciting the Beaux Arts Trio has ever presented at Harvard. It begins with the Haydn Trio No. 27 and the Brahms Piano Quartet No. 1, with guest violist Samuel Rhodes. The group will then be joined by bassist Georg Hortnagel for a performance of the famous Schubert "Trout" quintet, an all-time favorite among chamber music lovers. Hortnagel is flying in from Munich just for this special occasion.

Since the Trio's return in 1978, Harvard has become a favorite stop along its world tour. The beauty of Sanders Theater and the especially appreciative attitude of the audience combine to make Harvard an ideal spot to play their music. Pressler points to "a feeling that the audience comes somewhat prepared, emotionally and mentally, for the music they are going to hear. The attentiveness and sense of participation of the audience is quite remarkable." Pressler and his colleagues consider Sanders among the finest halls in the world in which to play chamber music--"an acoustic marvel," says Greenhouse. "Sanders is a most beautiful sounding theater," continues Pressler. "There is only one problem: no backstage. You go from playing in that beautiful hall, and when you leave the stage you must stand in that cold, cold corridor."

Harvard is but one of the hundreds of stops for the Trio during its exhausting year-long anniversary celebration. Indeed, the touring schedule has been so full that what the gentlemen are really looking forward to now is a little rest. After that, they plan to continue exactly what they've been doing for the last quarter-century. How long will the Trio continue to play together? Pressler responds: "As long as the good feeling and decent living lasts."

Greenhouse is quite protective of his Stradivarius, and he always carries it on board airplanes with him. Due to its size, the cello flies first class, while the cellist flies coach.