There is a wonderful part of The Camelot Project at the University of Rochester; it's an article about The Questing Beast. There's a background essay, with seven different illustrations in the gallery. Here are my two favorites from that gallery, and you can also learn more at Wikipedia.
Arthur Rackham, from The Romance of King Arthur and His Knights of the Round Table (1917)
One of my favorite book illustrators is Willy Pogany, so I thought I would write up a post with some of his work; you can see his illustrations in the Turkish Fairy Tales unit for class. You can read more about him at Wikipedia.
The word labyrinth comes to English from Greek, and it is connected to the story of the famous labyrinth which Daedalus built for King Minos in which King Minos imprisoned the Minotaur; later, the hero Theseus was able to enter the labyrinth, slay the Minotaur, and find his way back out, with the help of Ariadne's thread. You can read all about Daedalus, Minos, the Minotaur, Theseus, and Ariadne at Wikipedia.
Here is a nifty poster of Fairy Tale Composers and Collectors from Fairylogue Press.
The poster includes many authors; I've bolded the ones who are part of the UnTextbook: Charles Perrault, Andrew Lang, Brothers Grimm, Yei Theodora Ozaki, J. M. Barrie, Madame D'Aulnoy, P. Chaykovsky, Scheherazade, Hans Christian Andersen, Joseph Jacobs, Alexander Afanasyev, Asbjornsen and Moe, George MacDonald, L. Frank Baum, Lewis Carroll, Carlo Collodi, Robert Southey, Mademoiselle de La Force, and Marie Leprince de Beaumont.