Navaho medicine man and sand painter Hosteen Klah bridged the long span from the old days of tribal greatness and warfare to the new days of tribal greatness and warfare to the new days of change and adjustment. Thus the story of Klah told here is also the story of his prominent family and reflects nearly two hundred important years of Navaho history.   Klah's great-grandfather, Narbona, was war chief of the Navahos during their heyday. His mother made the "Long Walk" to the Bosque Redondo (Fort Sumner). After Klah was born in 1867, one year before the treaty establishing the Navaho Reservation, his family moved back to their ancestral land and slowly regained their former wealth.   The most influential medicine man on the Reservation, Klah also became an expert weaver. Many of his sand-painting designs were woven on tapestries and so preserved, for he and no successor. The Museum of Navajo Ceremonial Art at Santa Fe has its nucleus Klah's tapestries, ceremonial effects, and drawings of his sand paintings.