A book is usually not considered a machine—though it is common to use paper as one of the book’s core elements and a machine to print its pages.If you open a book called Paper Machines on page 95, you may read about an incident where nothing less than a historical change within the long tradition of economical bookkeeping was invented. This crucial scene took place in a Boston company called Library Bureau and it was lead by America’s foremost librarian of the 19th century: Melvil Dewey, the inventor of the famous library classification system.Dewey’s secretary, E.W. Sherman, also plays a major role. She used card catalogs not only for libraries but for her own commercial bookkeeping, and her visionary insight in applying library furniture to financial transactions leads to the ubiquitous spread of card indexes on every office desk around 1900.However, this is only one small episode in a longer trajectory. Others could be mentioned. For example, around 1700, the famous polymath Gottfried Wilhelm Leibniz stored his information in a specially designed cupboard on paper slips which were hooked on long battens, freely moveable and arrangeable in new orders. Or, the Nobel prize winner in Chemistry, Wilhelm Ostwald, sought to store all available information of all time and all nations at one single spot in Munich in a huge collection of index cards. This project, called The World Brain, began in 1911 and ended already in 1913 with a tiny collection of postcards of the Bavarian town of Ansbach.What happens if you suddenly realize that your personal card index knows more than you? How can this sometimes intimate relationship be described? And what are the poetological effects on the writing scene if you simply communicate with your wooden as well as learned machine—your externalized brain which even promises to write your texts?The personal slip box offers an interface which is more than just a pleasant sight of an apparatus made either from paper and wood or from bits and bytes. The apparatus delivers those keywords which stimulate the scholar to further thought production in response to a simple touch of the interface. The previously silent Other becomes a proper interlocuter. The finely-branched network of connections guarantees that the keywords which are subsequently exchanged appear by no means haphazardly. For over the course of the operation, these keywords gradually cultivate a kind of second memory. And the apparatus itself serves, to borrow Immanuel Kant’s phrase, as a “midwifery of thought.”Paper Machines not only gives answers to those questions, it also provides the appropriate praise of the link or cross-reference as a productive way of imagining new thoughts and lines of argumentation. If reading the book would inspire others to rethink their way of handling information or to start wondering how the media determines our way of thinking itself, a step into a flourishing discipline would have been taken: Welcome to Media Theory!