Professor Kirke is the fictional professor who shelters the Pevensie children in The Lion, the Witch and the Wardrobe.
The professor lives in a large country house where Peter, Susan, Edmund, and Lucy stay during the Second World War. Lucy discovers the wardrobe that leads to Narnia, and Professor Kirke later responds more seriously than the adults who dismiss her account. His reasoning about the children’s story is one of the novel’s memorable early clues.
Professor Kirke is also important beyond the first published Narnia book. He is identified as Digory Kirke, the boy who appears in The Magician’s Nephew, the prequel that explains the origins of the wardrobe and several features of Narnia.
The answer is normally given as Professor Kirke, although Digory is his first name. “Professor Digory” is not the standard form used in The Lion, the Witch and the Wardrobe.