Johann Weyer was physician to the Duke of Cleves, and his book of 1563 is the first sustained attempt to argue the accused out of the dock using medicine rather than theology. Its structure matters. Weyer does not begin by denying demons. He grants a great deal about them, and then turns the concession into a weapon.
If the Devil is powerful and deceitful, he argues, then the obvious reading of an old woman confessing to flying to a gathering and blighting a field is not that she did it. It is that she is deceived, or melancholic, or ill, or exhausted, or persuaded by the questioning itself. She lacks the capacity to have done what she says she has done. A court that executes her is punishing a delusion, and the delusion is the Devil's work rather than hers. Weyer describes cases from his own practice, and the descriptions read as clinical observation rather than as demonology.
He was not evenhanded, and the asymmetry is part of the argument. Weyer was severe about the learned male magicians who worked with grimoires and conjurations, on the ground that they acted knowingly and sought demonic help deliberately. His sympathy went to the poor and mostly elderly women who had sought nothing and understood less. Whatever else this is, it is the first widely read book to look at a witch trial and see a patient rather than a defendant.