From a review of Riding Spirits of the Dead: A Study of the Possession of Abd al-Radi and of Ghosts and Demons, Saints and the Ecstatic, the Cult of the Dead and Priesthood in an Upper Egyptian Village, a book on spirit summoning in Upper Egypt, in al-Masri al-Youm:
Winkler spent four months studying Abd al-Radi, attending many sessions where the young peasant was possessed by his uncle and other spirits of people who, when they were alive, were known for their supernatural abilities. These sessions included Abd al-Radi, his father, and the visitors. Incense was used to prepare the medium for possession by the spirit. Winkler states in his studies that Abd al-Radi (or Bakhit) saw images of Winkler’s wife, children, and house in Tubingen. His predictions for the anthropologist’s future trips and correspondences turned out to be mostly true.