in his History of Mechanical Inventions  (p. 239) is masterly:

          The entire achievement embodied in the printed 
     book with illustrations presents a striking example of the 
     multiplicity of individual acts of invention that are 
     requisite to bring about a new result. In its entirety, this 
     accomplishment involves: the invention of paper and of 
     inks made with an oil base; the development of engraving 
     on wood and. . . of wood blocks; the development of the 
     press and the special technique of press work involved in 
     printing.
          The history of paper is in some ways a separate 
     subject, but it must be evident that the generalization of 
     printing could not have proceeded significantly with any 
     other basic medium. Parchment is difficult to handle, 
     costly, and narrowly limited in supply. Books would have