In his book "The Exploration of the Canyons of the Colorado", Powell is motivated to conduct ethnologic studies because "these Indians are more nearly in their primate condition than any others on the continent with whom I am acquainted." As Wallace Stegner posits in "Beyond the 100th Meridian", by 1869, many Native American tribes had been pushed to extinction, and those that were known were considered corrupted by intercultural exchange. Even in 1939, Julian Steward, an anthropologist compiling photographs from Powell’s 1873 expedition suggested that: “Fascinated at finding Americans nearly untouched by civilization, he developed a deep interest in ethnology ... Few explorers in the United States have had a comparable opportunity to study and photograph Indians so nearly in their aboriginal state.”