Duffy and the Devil was a popular play in Cornwall in the nineteenth century, performed at the Christmas season by groups of young people who went from house to house. The Zemachs have interpreted the folk tale which the play dramatized, recognizable as a version of the widespread Rumpelstiltskin story. Its main themes are familiar, but the character and details of this picture book are entirely Cornish, as robust and distinctive as the higgledy-piggledy,...