Bethany Beardslee (born December 25, 1925) is an American soprano particularly noted for her collaborations with major 20th-century composers, such as Igor Stravinsky, Milton Babbitt, Pierre Boulez, George Perle, Sir Peter Maxwell Davies and her performances of great contemporary classical music by Arnold Schoenberg, Alban Berg, Anton Webern. Her legacy amongst midcentury composers was as a "composer's singer"—for her commitment to the highest art of new music. Milton Babbitt said of her "She manages to learn music no one else in the world can. She can work, work, work." In a 1961 interview for Newsweek, Beardslee flaunted her unflinching repertoire and disdain for commercialism: "I don't think in terms of the public... Music is for the musicians. If the public wants to come along and study it, fine. I don't go and try to tell a scientist his business because I don't know anything about it. Music is just the same way. Music is not entertainment."
Beardslee was born in Lansing, Michigan. She trained first in the Music Department of Michigan State College, where she received her B.M. (cum laude), and later did post-graduate work at the Juilliard School. She trained with Louise Zemlinsky (wife of Alexander Zemlinsky) She received an honorary doctorate from Princeton University in 1978, an honorary Ph.D. New School for Music Philadelphia, PA in 1984, and from the New England Conservatory in 1994.
Her first husband, the French conductor Jacques-Louis Monod, whom she married in 1951, introduced her to the basic vocal repertoire of the Second Viennese School. Together they toured the United States through the 1950s and gave recitals of this literature combined with basic Lieder. Monod's influence brought Beardslee onto the path that would become her career in contemporary classical music.