Another important 20th-century thinker to rely on index cards was pioneering media theo-rist Harold Innis.18 The executors of his estate published a tome called The Idea File (1980),composed of 18 inches of index cards, plus five inches of reference cards. Innis had a selection ofhand-written index cards typed up and numbered, 1 through 339. It is unclear if these rumina-tions on television and art, communication and trade, secrecy and money, literature and the oraltradition, archives and history were intended to constitute a book project; the decision to publishthe cards balances the putative will to posterity of an author, and the potential embarrassmentof incomplete work. Clearly Innis intended to work synchronically rather than diachronically,to focus less on logical connections than on analogies, to practice pattern recognition—andthe associative links of a card index lend themselves perfectly to this kind of project.