George London, 64, one of the greatest dramatic baritones in the history of opera, died Sunday at his home in Armonk, N.Y. The cause of death was not immediately available.

Mr. London, who became intimately associated with music in Washington as artistic director of the Kennedy Center and general director of the Washington Opera in the latter stages of his career, was born in Montreal but moved to Los Angeles in 1935, where he began studying voice.

From this beginning there followed a career that took him to the Metropolitan Opera, and to starring roles in Salzburg, Moscow, La Scala in Milan, the Wagnerian shrine at Bayreuth, and the Vienna State Opera, where he was acclaimed, not only for his magnificent voice and acting, but for his good looks and slim elegance, which, according to the historian of the Vienna State Opera, made him "the heartthrob of every girl in the audience."

Born George Burnstein, he took the more stage-suited name of London shortly before his debut in opera, which came when he was 21, in "Gainsborough's Duchess," an opera by the English composer Albert Coates. That was in 1941. Not long after that, he was the baritone in a popular touring trio called Bel Canto, whose tenor was Mario Lanza, with soprano Frances Yeend.

In 1949, Mr. London left this country for Europe, as many singers of that generation did, and quickly found stardom. In that same year, he made his debut in Vienna as Amonasro in Verdi's "Aida," following that in successive seasons in the title role of Mozart's "Don Giovanni," the four villainous roles in "The Tales of Hoffman," Almaviva in "The Marriage of Figaro," Scarpia in "Tosca," Mandryka in "Arabella," by Richard Strauss, and, in 1953, the role of Boris in Mussorgsky's "Boris Godunov."

It was in this last role that he made his debut at the world-famed Bolshoi Theater in Moscow, the first American ever to sing on that stage. Mr. London sang in Russian with such beautiful enunciation that his instant fans in Moscow could not believe he could not speak the language offstage.

He had everything needed for the greatest kind of international career: a superb voice of basically darker hues, which he controlled with the kind of ease that let him toss off Don Giovanni's Champagne Aria with the kind of sexy allure called for in the part; a figure that gave his 6-foot-plus height the ability to suggest Scarpia's menace, Wotan's majesty and Amonasro's regal demeanor. Along with the voice was a flare for languages, so that he sang with a kind of clarity many singers never achieved in English, French, German, Italian and Russian, making them all sound as if they were his native tongue. And to the vocal richness, he added unusual gifts as an actor.

Among the greatest mementos of a career that will remain for generations to admire is a film of the central duel from the second act of "Tosca," with Maria Callas in the title role. Here Mr. London can be seen and heard as a complete equal with the unparalleled soprano in one of the most searingly intense dramatic scenes in all of opera. His facial expression as Scarpia is as gripping as his eyes and his carriage were in the Hallucination Scene in "Boris Godunov," or as the evil manipulator Dapertutto in "The Tales of Hoffman."

His voice could sound black, for Scarpia, pure gold for Wotan, the epitome of elegance as the Count Almaviva and threateningly commanding when, as Amonasro, he forced Aida to obey his directions. He sang under the greatest conductors in the world during his career: Knappertsbusch, Boehm, Solti, Ormandy, Mitropoulos.

That career was tragically cut short in 1967 by a paralysis of the vocal cords which left him ease of speech but no longer the power and command to sing. After that point, he directed all of his energies to assisting young singers, in addition to narrations in such works as "Moses und Aron," by Schoenberg, and the same composer's earlier "Gurre-Lieder."

In 1968, Mr. London took on the duties of artistic director of the Kennedy Center -- its first -- and, in 1975, assumed the post of general manager of the Washington Opera and the National Opera Institute.

In this last post, he supervised nationwide auditions in which he listened always with both sympathy and an ear tuned to the promise that he knew rested in so many young American singers. Under his direction, the Opera Institute gave grants of $5,000, renewable for a second year in the same amount, to young artists, many of whom are now leading stars in the world's opera houses.

Once, hearing a young tenor who is now a star at the Metropolitan Opera and in Europe, Mr. London said, "My friend, you have a wonderful voice. But you cannot think of going onstage with those glasses! Have you ever thought of contact lenses? You must!" It was that kind of direct, down-to-earth advice -- advice that might have seemed all too apparent, but which he knew was essential -- that he was always happy to give young talented singers.

While he made his reputation by singing in many of the world's greatest opera houses, he was also sought after by symphony orchestras for appearances in such dramatic works as Verdi's "Requiem," as well as for the world premiere of such music as Paul Hindemith's "When Lilacs Last in the Dooryard Bloomed," which he later sang in Washington Cathedral. He also sang the title role in the U.S. premiere of Gian Carlos Menotti's "The Last Savage" when it had its first performance at the Metropolitan Opera in 1964. Much of his finest singing can be heard on recordings, in complete operas, in song cycles, and in scenes from opera and Broadway musicals.

Mr. London is survived by his wife, Nora, and two children.