Closely related to the development of American music in the early 20th century was the emergence of a new, and distinctively American, art form -- modern dance. Among the early innovators was Isadora Duncan (1878-1927), who stressed pure, unstructured movement in lieu of the positions of classical ballet.

The main line of development, however, runs from the dance company of Ruth St. Denis (1878-1968) and her husband-partner, Ted Shawn (1891-1972). Her pupil Doris Humphrey (1895-1958) looked outward for inspiration, to society and human conflict. Another pupil of St. Denis, Martha Graham (1893-1991), whose New York-based company became perhaps the best known in modern dance, sought to express an inward-based passion. Many of Graham's most popular works were produced in collaboration with leading American composers -- "Appalachian Spring" with Aaron Copland, for example.

Later choreographers searched for new methods of expression. Merce Cunningham (1919- ) introduced improvisation and random movement into performances. Alvin Ailey (1931-1989) incorporated African dance elements and black music into his works. Recently such choreographers as Mark Morris (1956- ) and Liz Lerman (1947-) have defied the convention that dancers must be thin and young. Their belief, put into action in their hiring practices and performances, is that graceful, exciting movement is not restricted by age or body type.

In the early 20th century U.S. audiences also were introduced to classical ballet by touring companies of European dancers. The first American ballet troupes were founded in the 1930s, when dancers and choreographers teamed up with visionary lovers of ballet such as Lincoln Kirstein (1907-1996). Kirstein invited Russian choreographer George Balanchine (1904-1983) to the United States in 1933, and the two established the School of American Ballet, which became the New York City Ballet in 1948. Ballet manager and publicity agent Richard Pleasant (1909-1961) founded America's second leading ballet organization, American Ballet Theatre, with dancer and patron Lucia Chase (1907-1986) in 1940.

Paradoxically, native-born directors like Pleasant included Russian classics in their repertoires, while Balanchine announced that his new American company was predicated on distinguished music and new works in the classical idiom, not the standard repertory of the past. Since then, the American ballet scene has been a mix of classic revivals and original works, choreographed by such talented former dancers as Jerome Robbins (1918- ), Robert Joffrey (1930-1988), Eliot Feld (1942- ), Arthur Mitchell (1934- ), and Mikhail Baryshnikov (1948- ).