Walking fish, knights fighting snails, murderous rabbits, mischievous monkeys, The images in the margins of many medieval manuscripts, both holy and secular, can be saintly and beautiful - but also playful, crude, demonic and downright bizarre.What are the beliefs, inventions and ideas which led the illuminators to produce such strange images in the margins of their books?Dr Alixe Bovey explores the world of medieval marginalia.Producer Jo WheelerA Freewheel production for BBC Radio 4