Ruth Sawtell Wallis was born in Springfield, Massachusetts, and graduated in 1919 from Radcliffe College with a bachelor's degree in English. She then enrolled in the graduate degree program in anthropology, winning a scholarship to travel to Europe to do research. She was the first to discover Azilian (an early Mesolithic culture) remains in France, uncovering two burial sites at Montardit, Ariège. On her return to the USA, she switched to the anthropology program at Columbia University in New York to study under Franz Boas. In 1930, after earning her Ph.D., she was hired by the anthropology department at the University of Iowa. The following year, she married Wilson Dallam Wallis, a professor of anthropology at the University of Minnesota, and became an assistant professor of sociology at Hamline University in St. Paul. She was fired from her position because it was considered out of the question for two academics in one family to be employed during the Great Depression. Later, working for the Bureau of Home Economics, she undertook the largest-ever study of children's growth, which ultimately made it possible to standardize children's clothing sizes. During World War II, she analyzed labor statistics for the War Manpower Commission and helped coordinate the Japanese Language and Culture Program for the U.S. Army. She also began writing successful mystery novels, and published a total of five, beginning with Too Many Bones (1943). In the 1950s, she studied native peoples in Canada and the USA. After moving to Connecticut with her family, she was named a sociology lecturer at Annhurst College in South Woodstock, and rose to become full professor before retiring in 1974.