 John Man's quoted Gutenberg page sizes are in a proportion not very close to the golden ratio, but Rosarivo's or van de Graaf's construction is applied by Tschichold to make a pleasing type area on pages of arbitrary proportions, even such accidental ones.Richard Hendel, associate director of the University of North Carolina Press, describes book design as a craft with its own traditions and a relatively small body of accepted rules.The dust cover of his book, "On Book Design", features the Van de Graaf canon.