D.P. WalkerD. P. Walker (1914–1985) was trained at Oxford and spent most of his career at the Warburg Institute of the University of London. His other books are The Decline of Hell (1964), The Ancient Theology (1972), and Unclean Spirits: Possesion and Exorcism in France and England in the Late Sixteenth and Early Seventeenth Centuries (1981). Read More Read Less