In "Black Elk Speaks" and "When the Tree Flowered," John C. Neihardt recorded the teachings of the Oglala holy man Black Elk, who had, in a vision, seen himself as the "sixth grandfather," the spiritual representative of the earth and of mankind. Raymond J. DeMallie makes available for the first time the transcripts from Neihardt's interviews with Black Elk in 1931 and 1944, which formed the basis for the two books. His introduction offers new insights into the life of Black Elk.