Ella Cara Deloria was born on the Yankton Indian Reservation in southeastern South Dakota, near today's town of Lake Andes. Her parents were both of mixed Yankton Sioux and European-American descent. Her father, an Episcopal priest, was in charge of St. Elizabeth's Church in Wakpala. She attended St. Elizabeth's primary school and All Saints, an Episcopal boarding school in Sioux Falls. In 1910, she entered Oberlin College on a scholarship, then transferred to Columbia Teachers College, where she earned a bachelor of science degree. At Columbia, she met the noted anthropologist Franz Boas, who hired her for her ability to speak the Lakota language to his students. This was her introduction to a career focused on the study of American Indian languages and cultures. She went back to South Dakota to teach and supervise health education in Indian schools from 1915 to 1923, then taught dance and physical education at Haskell Indian school in Lawrence, Kansas. From 1928 until 1938, she studied the language, recorded stories and ethnographic material from Lakota and Dakota elders throughout South Dakota and in Minnesota. She also translated historical texts written by tribal members. Her first professional publication was a translation, The Sun Dance of the Oglala Sioux (1929). Her collaboration with Boas produced a co-authored grammar of Lakota, published in 1941 and now considered a classic of American Indian language description. She carried out her ethnographic studies under the supervision of Ruth Benedict, who was Boas's assistant and colleague. After Boas's death in 1942, Ella Deloria continued to collaborate with Ruth Benedict until the latter's death in 1948. She recorded a large number of myths and sacred stories, many of which were published in Lakota and English. As assistant director of the W. H. Over Museum at the University of South Dakota, she became a member of the new Institute for Indian Studies and received a National Science Foundation grant that supported work on a Lakota dictionary from 1962 to 1966. Her novel Waterlily was written in the 1940s but she could not find a publisher; it did not appear in print until 1988, years after her death. It quickly became the most widely read of her works.