Robert Parris, 75, an established Washington composer, music professor, pianist and expert harpsichordist, died of congestive heart failure Dec. 5 at George Washington University Hospital. He had lung cancer.

Mr. Parris wrote dozens of notable works in the last quarter century, some of which were performed by the National Symphony Orchestra, the Seattle Symphony and the National Symphony of Mexico. Among his best known works are the two "Books of Imaginary Beings" for chamber ensemble and "Symphonic Variations," which was premiered in 1987 by the National Symphony.

He achieved artistic success and critical acclaim in the Washington music community while teaching music composition and theory at George Washington University for the last 37 years.

In all, he wrote about 80 pieces in a variety of the major forms of music, including solos and quintet chamber ensembles.

Some have become popular recital material at Contemporary Music Forum-sponsored concerts at the Corcoran Gallery of Art and Lisner Auditorium, and some of his works were recorded on a compact disc on the CRI label in 1998.

Washington Post music critic Joseph McLellan once described Mr. Parris, who also composed pieces for productions at the Shakespeare Theatre at the Folger, as a "composer of luxuriant imagination, aided by a brilliant sense of instrumental color and tempered by structural discipline."

Reflecting on his musical style, Mr. Parris described his compositions as "accessible, not radical" and "an amalgam of all the forces around me."

Mr. Parris, a Chevy Chase resident, was born in Philadelphia. He began private study of piano and music theory in his teens. Composition had become his overriding interest by the time he enrolled at the University of Pennsylvania, from which he graduated and received a master's degree in music education.

In 1946, he graduated from the Juilliard School of Music, where he studied composition with Peter Mennin and William Bergsma. He taught piano, theory and composition at what is now Washington State University in Pullman, Wash., before receiving a Fulbright Fellowship in 1952 to study with Arthur Honegger at the Ecole Normale de Musique in Paris.

Upon his return from Europe, he settled in Washington, where he worked briefly as a clerk at the Library of Congress, taught piano and composition privately and wrote music criticism for The Washington Post and the Washington Star.

He began teaching at the University of Maryland in 1961, and a year later, he joined the faculty of George Washington University.

His hobbies included reading, cooking and growing roses.

Survivors include his wife of 27 years, Anna Elkes Parris, and their daughter, Laura Parris, both of Chevy Chase; and a brother, Tony Parris of Philadelphia.