Johann Weyer (Weier, Wier, Wierus, Piscinarius) (1515-1588) was a pioneer in the fields of medicine and psychiatry. He was also a firm believer in magic, and was in fact a student of one of the most famous occultists of all time, H. C. Agrippa. His Praestigiis Daemonum (1563) was basically a point-by-point rebuttal of the hateful witch hunter's handbook, Malleus Maleficarum. His book includes interesting reports of Faust, Agrippa, and Trithemius from a contemporary witness. Sigmund Freud calls the Praestigiis Daemonum one of the ten most significant books of all time.