Ruth St. Denis (1879-1968) was a dancer, choreographer and teacher, and one of the founders of the Denishawn School of Dance.

St. Denis was born in New Jersey and spent her childhood on a farm in Somerville with her parents, Ruth Emma Hull Dennis, a physician, and Thomas L. Dennis, a machinist and inventor. Ruth learned exercises from the Delsarte system of expression from her mother. She also took dance classes in New Jersey and briefly studied ballet with Madame Bonfanti in New York City, She began her professional career with minor roles in musical plays, appearing as a "skirt-dancer," acrobat, high-kicker, model and actress.

In 1904, touring with David Belasco's Madame Dubarry, Ruth was inspired by a cigarette poster depicting the Egyptian goddess Isis and by her readings in Eastern philosophy and mysticism to turn her career toward the exploration of dance as a serious art form. She premiered her first important solo dance, "Radha," in 1906 on the variety bill of a Sunday night smokers concert. "Radha" baffled the vaudeville critics, blending theatrical gestures and physical allure with spirituality; some found it too slow and serious for vaudeville, but it set the tone for her later dances, most of which dealt in some measure with transformation.

In 1914, St. Denis met Ted Shawn and hired him as her partner; before the year was out, they were married. Together they founded the Denishawn schools and company, which thrived until 1932, when St. Denis and Shawn decided to pursue separate careers. The era of Denishawn greatly influenced the art of dance in America and produced such dancers as Martha Graham, Doris Humphrey, and Charles Weidman.

During World War II, St. Denis moved to California, where she lived with her brother and contributed to the war effort by working at the Douglas Aircraft Factory and participating in benefits for allied causes. She also established a new studio on Cahuenga Boulevard in Hollywood, which served as her headquarters for the rest of her life. During the late 1940s and 1950s, St. Denis devoted most of her time to the Ruth St. Denis Foundation, which aimed to establish a church in which dance and related arts were dedicated to religious service; she also performed frequently at Jacob's Pillow both as a solo artist and with Ted Shawn. Ruth St. Denis died of a stroke on July 21, 1968. In addition to many articles, she published An Unfinished Life, her autobiography (1939) and Lotus Light, a book of poems (1932).