Ishi in Two Worlds is a biographical account of Ishi, the last known member of the Yahi Native American people. Written by American author Theodora Kroeber, it was first published in 1961. Ishi had been found alone and starving outside Oroville, California, in 1911. He was befriended by the anthropologists Alfred Louis Kroeber and Thomas Waterman, who took him to the Museum of Anthropology in San Francisco. There, he was studied by the anthropologists, before his death in 1916. Theodora Kroeber married Alfred Kroeber in 1926. Though she had never met Ishi, she decided to write a biography of him because her husband did not feel able to do so.