If only Robert and Felix come to mind when you hear the names Schumann and Mendelssohn, think again.

For many years Clara Schumann and Fanny Mendelssohn, composers in their own right, lingered in the parentheses of discussions about the more famous men in their lives. And yet, in the world of classical music, they are closer to being household names than just about any other female composers.

Major orchestras are still reluctant to invest the time, money and commitment to put large-scale compositions by women in the concert spotlight. But compared with the past eight centuries, the past two decades have been boom times: scholars, book publishers and recording companies are putting an astonishing number of compositions by these two women and many others on the record.

In the early 1990s MacMillan Publishing came knocking on Sylvia Glickman's door and asked her to co-edit "Women Composers: Music Through the Ages," a 12-volume anthology beginning with the songs of the 9th-century nun Kassia.

"I guess they thought, Gee, it's really time to do something about women composers,' " says Glickman, a composer, pianist and founder of Hildegard Publishing Co., a seven-year-old music press in Bryn Mawr, Pa.

The anthology will profile the lives and music of some 300 women. That's just the tip of the iceberg, says Glickman, who notes that Aaron Cohen's 1987 International Encyclopedia of Women Composers lists more than 6,000 names.

So where does the novice listener begin? Glickman and other experts suggest a few of the classical heavyweights on concert programs and compact disc:

Hildegard von Bingen, a 12th-century Benedictine abbess, was not only a composer but also a poet, mystic, teacher, scientist and the confidante of popes and politicians. Her ethereal liturgical songs, available on several recent recordings, have become standards in the medieval chant craze of our own time.

Clara Wieck Schumann (1819-1896) was considered one of the finest pianists of her generation. Her German father saw to it that she had the best musical training available, and with a formal debut at age 11 she was on her way to becoming Europe's "queen of the piano." Despite a long and bitter lawsuit with her father, who refused to consent to a match with his student Robert Schumann, she married the unknown composer in 1840. Although Robert supported Clara's efforts, her composition work took a back seat to his, and she concentrated on furthering the careers of both her husband and young Johannes Brahms. Clara Schumann gave birth to eight children; when her husband died in a hospital two years after a suicide attempt, she managed to continue a dazzling performance career. As a composer she is best known for her Piano Trio, Op. 17, songs, and music for solo piano. Compared with the eight pages of current CD recordings listed in the Schwann Opus catalogue under her husband's name, the recordings under Clara's name are contained within a few inches of print.

Fanny Mendelssohn Hensel (1805-1847) wrote some 500 compositions, only a fraction of which have been published. She led an intellectually lively life and played a large role in shaping some of the compositions by her younger and more famous brother Felix. Fanny Mendelssohn's letters and diaries reveal a witty, perceptive and intelligent woman, writes Marcia J. Citron in the comprehensive "Norton/Grove Dictionary of Women Composers" (MacMillan, 1995). Her strong self-image in this regard contrasts with her shaky confidence in her creativity (not uncommon in female composers). Some of her works and some by Clara Schumann appear on a CD recorded by the Women's Philharmonic and available through the orchestra's Berkeley, Calif., headquarters.

Amy Beach (1867-1944), the grande dame of American classical music, was celebrated during her lifetime as the country's foremost female composer. Born in New England to musical parents, Amy Cheney was encouraged in her career by H.W. Longfellow, Percy Goetschius, Oliver Wendell Holmes and physician Henry Harris Aubrey Beach, who became her husband in 1885. Beach's orchestral commissions paralleled a remarkable era in American history: her "Festival Jubilate" was written for the opening of the Women's Building at the World's Columbian Exposition in Chicago in 1893, while her "Panama Hymn" celebrated the International Panama Pacific Exposition in San Francisco. Beach used her status to further the careers of many young female composers; today, close to 25 CDs feature some of the 300 works she wrote in her lifetime.

Ellen Taaffe Zwilich, 57, is on everyone's short list of notable living American composers. Her Symphony No. 1 made her, in 1983, the first woman to win the Pulitzer Prize in Music. She is also the first appointee to Carnegie Hall's Composer's Chair; "Peanuts Gallery," her new composition for piano and orchestra based on Charles Schulz's cartoon, will debut at the hall March 22. Zwilich's recent works take a more melodic approach than her earlier atonal style. About 15 of her compositions are available on CD.

Joan Tower, winner of the prestigious 1990 Grawemeyer Award for Music Composition, has seen her strongly rhythmic works performed by the St. Louis, Chicago, Louisville, Indianapolis, Dallas and Berlin Radio symphony orchestras. She is likely to receive increased attention with the approach of her 60th birthday next year.

Libby Larsen, 46, a prolific composer, continues to blend electronic and acoustic sound in her symphonies, operas and smaller biographical pieces based on strong-minded women such as Calamity Jane, Georgia O'Keeffe and Mary Cassatt.

IAWM s Web site at http://music.acu. edu/www/iawm/home.html is an excellent starting place for information about contemporary female composers. Internet users will find links to specialty publishers and CD distributors, including Arsis Press, Hildegard Publishing, Leonarda Productions and Editions Ars Femina in New York City, and Vivace Press in Pullman, Wash.

The site lists events on the IAWM calendar, and offers a helpful bibliography of primers such as "Women Making Music: The Western Art Tradition, 1150-1950," edited by Jane Bowers and Judith Tick (University of Chicago Press, 1986); "Unsung: A History of Women in American Music" by Christine Ammer (Greenwood Publishing, 1980); "Women Composers: The Lost Tradition Found" by Diane Peacock Jezic (The Feminist Press, 1994); and "The Pandora Guide to Women Composers: Britain and the United States, 1629-Present" by Sophie Fuller (Pandora, 1994). CAPTION: Clara Wick Schumann, wife of Robert. CAPTION: Fanny Mendelssohn Hensel, sister of Felix. CAPTION: Amy Beach, above, is the grande dame of female American composers. Libby Larsen, left, carries on the tradition today.