Prior to 1978
Wilbert Slinkhard was a wizard who authored the book Defensive Magical Theory, which was approved by the British Ministry of Magic as a suitable textbook for Defence Against the Dark Arts classes. Due to the peaceful approaches to confrontation Slinkhard indoctrinated, Dolores Umbridge found his work useful in her classes during the 1995-1996 school year due to the Ministry's paranoid view that the students were being trained in combat.
Personality and traits
If the contents of his masterwork are any indication of his personality or views on the subject, Slinkhard was a pacifist, advocating a passive approach to confrontation and discouraging the use of combative spells for even defensive purposes. He deemed "counter-jinx" an inappropriate term to use for the spells, stating that such was only to make them seem more acceptable.
The name "Wilbert" means "bright will", derived from the Germanic elements wil "will, desire" and beraht "bright".
- Harry Potter and the Order of the Phoenix (Mentioned only)