There was quite a lot of Bach and Scarlatti at Thursday night's installment of the Mostly Mozart Festival, and there was even a little bit of Vivaldi, curiously rearranged, but not a single note of Wolfgang Amadeus Mozart.

Still, nobody in the Kennedy Center Concert Hall seemed disappointed. If the concert ignored the namesake of the four-day festival, it richly fulfilled the promise of its own title: "Bach Harpsichord Extravaganza." The four harpsichord players did not exactly outnumber the capable 12-member orchestra, the New York Chamber Soloists, but when they all got together, they could easily produce more notes than the orchestra.

Kenneth Cooper was the best known of the four and turned in the most flamboyant performances, but distinguished work was also done by J. Reilly Lewis -- crisp, precise and technically brilliant; Arthur Haas, who used some wonderfully expressive tempo fluctuations in slow passages; and Edward Brewer, whose phrasing and choice of registrations were outstanding. These qualities, and others too numerous to cite, became evident in a pre-concert recital that featured the players, one at a time, in tiny but marvelously inventive sonatas by Domenico Scarlatti.

Ten sonatas were played, a small sample of Scarlatti's 500-plus works for harpsichord; listening to the endless variety he worked into these miniatures, with echoes of marches, operatic arias, Spanish and Italian folk music and all kinds of dances, one wondered how a "Simply Scarlatti" festival might work -- perhaps featuring an evening of Mozart.

Bach was the composer for all five concertos heard in the actual concert. Most of the works were more familiar in an earlier form, with violin soloists -- notably the Concerto in C Minor for two harpsichords, BWV 1060; the Concerto in D for one harpsichord, BWV 1054; and the Concerto in A Minor for four harpsichords, BWV 1065. The first two are well-known violin concertos by Bach -- among the greatest ever written. To my ears, they sound more idiomatic in their original form, but they also work well in Bach's rearrangement, and one would hate to deprive harpsichordists of such fine material. BWV 1065 was adapted by Bach from Vivaldi's brilliant Concerto in B Minor for four violins, Op. 3, No. 10. It sounds excellent in the Bach adaptation (you can still hear Vivaldi's violins chirping in the sound of Bach's harpsichords) and the four soloists performed together brilliantly, inspiring so much applause that they had to repeat the first movement as an encore.

Musically, however, the finest work of the evening may have been the Concerto in C for two harpsichords, BWV 1061, which was essentially an eloquent dialogue between Cooper and Lewis with minimal intervention by the orchestra.

Afterward, as is customary during the Mostly Mozart Festival, a substantial part of the audience went out on the River Terrace, where a group called Sidney's Orchestra Trio (one violin, one double bass, one electric keyboard and two loudspeakers) played music (mostly waltzes like "Wunderbar" and "Lover, When You're Near Me") while patrons danced, strolled, admired the backlighted fountain, the sliver of moon and the lights of Virginia across the river, and nibbled sandwiches and sipped drinks that the Kennedy Center had on sale.

When the orchestra offered to play requests, someone asked for "Mack the Knife." "Can we play that as a waltz?" Sidney wondered out loud. "Possibly. ... No; better not." So they played it as usual.

But Bach could have made it into a waltz -- if he had ever heard a waltz.

Saturday Night

In the hands of a great composer, an overture is living proof that good things come in little packages. The same may be said of an orchestra in the hands of a great conductor.

Saturday night at the Kennedy Center Concert Hall, director Gerard Schwarz led his modestly sized Mostly Mozart Festival Orchestra in a performance of Mozart's Overture to "The Impresario," K. 486, proving that this work is a gem and this orchestra -- on a good day -- is without parallel.

The proof was evident from the first few bars. Schwarz's subtle blend of woodwind color within and around the brilliant string work made for a vivid and intelligent reading. (The same held true for the Haydn "London" Symphony No. 104 in D, which closed the program.) There was playfulness here and an exhilaration that made the music leap from the page. It also served as an excellent foil for the two concertos that followed.

Shura Cherkassky opened with a touching interpretation of the Mozart Piano Concerto in D Minor, K. 466, catching the translucent "Romanza" in all its glory.

Cherkassky, who has had a long and distinguished career, played, not surprisingly, with wisdom and finesse; but it was surprising to find such similar skills displayed by 19-year-old Gil Shaham, the soloist in Mozart's Violin Concerto No. 3 in G, K. 216. One rarely hears the slow movement played with such roseate warmth or that simple nine-note phrase with such engaging delicacy.

Cherkassky and Shaham were featured in a virtuosic pre-concert recital. Shaham opened with two expertly realized Paganini "Caprices," and Cherkassky closed with Bach's "Italian" Concerto and Liszt's Hungarian Rhapsody No. 2 in C-sharp Minor. A fine foretaste of the wit and subtlety to come. -- Mark Carrington

Friday Night

All told, with concert and pre-concert taken together (and who would pass up a chance to hear pianist Misha Dichter play the last Schubert sonata before the main event?), Friday evening's Mostly Mozart experience, featuring the Manhattan-based festival orchestra, lasted three full hours.

This is by today's standards dauntingly long. Moreover, when the program consists of nothing but masterpieces, as it often does in this festival, the kind of sustained concentration required from both audience and performers is enormous.

So how do these players keep up everyone's interest? The good old-fashioned way, fortunately. Conductor Gerard Schwarz and his excellent, small orchestra invested all the music on this program with great energy right on through to the Mozart symphony (No. 34) that ended the evening. He is a thorough conductor, by the way, and responds lovingly to a score's many details. His excitement infects his players.

Clarinetist Richard Stoltzman's boyish charms made for a bubbly Mozart concerto, if not an especially deep one. Dichter, a true professional, communed with Schwarz in a brilliant, at times voluptuous, consistently stylish Beethoven First Piano Concerto. And this only a short time after his thoughtful, lyrically fluid account of the Schubert. -- Gordon Sparber

Wednesday Night

A famous advertisement for Rolls-Royce automobiles once claimed, "At 60 miles an hour, all you hear is the ticking of the clock." Wednesday night, the audience hearing Gerard Schwartz conduct the Mostly Mozart Festival Orchestra at the Kennedy Center Concert Hall was given an equivalent musical joyride.

Under Schwartz's direction this orchestral engine runs superbly on most every occasion, and this performance was no exception. Mozart's "Eine Kleine Nachtmusik," K. 525, glowed with a gracious light, as did the closing "Haffner" Symphony No. 35 in D, K. 385.

But flawless performances do not make great ones. And last night both of those pieces lacked an earthiness and natural exuberance that no amount of fine detailing could replace.

Pleyel's Concerto for Flute and Orchestra, Ben. 106, played here by Jean-Pierre Rampal, was dispatched with equal glitter. But even Rampal's magnificent flourishes and cadenzas were insufficient to save this concerto from the obscurity it deserves.

Other performances were simply stunning. Anne-Marie McDermott, soloist in the Mozart Piano Concerto No. 25, K. 503, played with fluid grace throughout and with brilliance in the Allegretto. Rampal, in the pre-concert recital, caressed two Telemann fantasies as though they were the only pieces in the world. -- Mark Carrington