Ephraim Douglass Adams (December 18, 1865 – 1930) was an American educator, born in Decorah, Iowa and graduated from the University of Michigan in 1887. He took a post-graduate course also at his alma mater, receiving the degree of Ph.D. in 1890. In the same year he was appointed special agent in charge of street railways for the eleventh census. His earlier work was done at the University of Kansas, where he became assistant professor (1891) and associate professor (1894) of history and sociology and in 1899 professor of European history. He was made associate professor of history in Leland Stanford Junior University in 1902, and, four years later, full professor of history at Stanford University. Regarded as an expert on the American Civil War period, his work is widely cited. He is best known for Power of Ideals in American History.