I had forgotten about him. There's a Wikipedia article on Ishi.
Prior to the California Gold Rush, the Yahi population numbered approximately 400. In 1865, Ishi and his family were victims of the Three Knolls Massacre (40 killed), from which approximately 30 Yahi survived. The remaining Yahi escaped but went into hiding for the next 40 years after cattlemen killed about half of the survivors. In the fall of 1908 a group of surveyors came across the camp of an elderly woman, elderly man, and young girl. The latter two fled and the former hid herself in blankets to avoid detection, because she was sick and could not run. The surveyors ransacked the camp and took everything. The elderly woman, Ishi's mother, and other relatives soon died and Ishi was the last of his tribe. Being starved and having nowhere else to go, Ishi walked into the white man's world.
There have been several books written on Ishi:
Ishi is also depicted in Jed Riffe's award-winning documentary film Ishi: The Last Yahi and in the HBO drama The Last of His Tribe. In the latter film, Graham Greene, a member of the Oneida tribe in Canada, plays the role of Ishi