Volume I number 6
Cover by Keith Parkinson
"But do you really mean, Sir," said Peter, "that there could be other worlds -- all over the place, just around the corner, like that?
"Nothing is more probable," said the Professor, taking off his spectacles and beginning to polish them, while he muttered to himself, "I wonder what they do teach them at these schools."
-- Peter and the Professor, The Lion, the Witch and the Wardrobe, C.S. Lewis