Although Americans got started relatively late in the business of composing classical music, quite a few American compositions have already found their way into the world's classical Top 40. George Gershwin's "Rhapsody in Blue," which must be near the top of the list, has a most unusual recording on Musicmasters MMD 60113T, a set of two compact discs on which conductor Maurice Peress has reconstructed the concert in New York's Aeolian Hall, Feb. 24, 1924, when Paul Whiteman and his orchestra introduced the music to the world. While the Gershwin number, in its original orchestration, is the climax of the recording, the whole program is interesting as an effort to erase the boundaries between classical music and jazz. Quite a few other light classical pieces are played by the jazz band, including "Pomp and Circumstance," "To a Wild Rose" and "Donkey Serenade."

Gershwin and Whiteman's arranger Ferde Grofe' are also brought together on a new Telarc disc (CD 80086), in which "Catfish Row," Gershwin's symphonic suite from "Porgy and Bess," is coupled with Grofe''s ever-popular "Grand Canyon" Suite. The performance has the precision one expects from Erich Kunzel and the Cincinnati Pops, and Telarc's sound is almost scarily realistic, particularly in a recorded thunderstorm that is included as atmospheric background in "Grand Canyon."

Among the more serious pieces of American music, the most popular internationally may be Samuel Barber's Adagio for Strings, which has recently received even more attention because of its use in the sound track of "Platoon." An excellent performance by I Musici de Montreal can be heard on Chandos CHAN 8515, along with two other 20th-century classics for string orchestra, Bartok's Divertimento and Stravinsky's Concerto in D, in closely miked virtuoso performances that are hair raising.

American and Russian Top 40 classics were both on the agenda last August when American conductor Lawrence Leighton Smith and a recording crew from Sheffield Lab visited the Soviet Union for 10 days of performance and recording with the Moscow Philharmonic and its music director, Dmitri Kitayenko -- each conductor performing music of the other's country. The three records that emerged from this encounter (Sheffield Lab CD-25, CD-26 and CD-27) have been released under the collective title of "The Moscow Sessions" and they offer the rare spectacle of a Russian orchestra and conductor performing Copland, Gershwin, Griffes, Ives, Piston and Barber. The American selections include Copland's "Appalachian Spring," Piston's "The Incredible Flutist" and Ives' "The Unanswered Question," none of which the Moscow orchestra had played before these recordings. For first performances, these are remarkably well styled. American listeners may find the Copland a bit heavier in texture and less folksy in style than usual, but the Ives is properly evocative and mysterious, the Piston is nicely pensive and boisterous in the proper places, and the whole set has the air of a historic occasion.

A lot of excellent American music is still known only to a relatively small audience, although it would have widespread appeal if it were better known. On a Nonesuch disc (97914-2), flutist Carol Wincenc has assembled a half dozen works by Barber, Copland, Cowell, Foss, Del Tredici and Griffes that certainly fall into this category, and the result is a superbly played selection of enchanting music.

Composer Alan Hovhaness has always had a broad appeal to audiences but never really fit in with the American musical establishment, perhaps because he has followed his own path, composing music tinged with the styles of eastern cultures and often dedicated to mystical explorations of inner space. His music can be heard at its best on two discs from Crystal Records. CD 802 contains his "Saint Vartan" Symphony and his "Artik" Concerto for horn and strings. On CD 508, his "Armenian Rhapsody" and "Celestial Fantasy" are well performed by the members of the Israel Philharmonic.

Paul Hindemith was born and died in Germany, but from 1940 to 1953 he was a professor at Yale and essentially an American composer. Probably the best memento of those years is his deeply emotive cantata " 'When Lilacs Last in the Dooryard Bloom'd': A Requiem for Those We Love." It is dedicated to the memory of Franklin D. Roosevelt, who died in the closing months of World War II, and it uses effectively a text written by Walt Whitman in memory of Abraham Lincoln's death near the end of the Civil War. The work was commissioned by a young choral conductor named Robert Shaw, who 41 years later directs the Atlanta Symphony Orchestra and Chorus. On Telarc CD-80132, Shaw conducts that ensemble in a superb performance of the work.