What do they all mean--the lascivious ape, autophagic dragons, potbellied heads, harp-playing asses, arse-kissing priests, and somersaulting jongleurs to be found protruding from the edges of medieval buildings and in the margins of illuminated manuscripts? A groundbreaking, celebrated study of marginalia in mediaeval art, Michael Camille's Image on the Edge explores this riotous realm so often explained away as mere decoration or zany doodles, a...