While some of the conceptual models of the early hypertext pioneers resulted in prototypes, like Douglas Engelbart's NLS system, others remained nascent visions that influenced others, like Vannever Bush's Memex and Ted Nelson's Xanadu.
The first chapter of the book explains how technical artefacts can incorporate design elements from prior decades by retro-activation as well as by horizontal transfer and how “with technical evolution comes the capacity to co-opt innovations on a whim”. This chapter also provides Ted Nelson's definition of hypertext: “a body of written or pictorial material interconnected in such a complex way that it could not conveniently be presented or represented on paper”.
The second chapter describes Vannever Bush's memory extender, Memex. Although this device was never built, Bush's grafting of associative memory theory onto an analog computing model has endured despite the fact that “technical white papers are not known for their shelf life”. This vision also drew considerable funding to MIT. The third chapter describes Douglas Engelbart's NSL, which was envisioned as a means to augment the intellect. When NSL was finally demonstrated at the ACM/IEEE-CS Fall Joint Computer Conference in San Francisco in December 1968, Engelbart received a standing ovation from the more than 2000 engineering professionals in attendance. This conference was also Englebart's first debut of the mouse.
Chapter 4 describes Ted Nelson's Xanadu. Fifty years ago the engineering community did not take Ted Nelson's ideas about using computers to support writing seriously, as computers were used for scientific calculations and corporate tasks and only appeared in large institutions. According to Belinda Barnet, “The important thing about this design is that it exploited the storage and display functions of a computer”. Chapter 5 describes the contributions of Adries van Dam. He and Nelson co-designed the Hypertext Editing System (HES), and van Dam's students developed it. Van Dam and his students also designed the File Retrieval Editing System (FRESS). Finally, Chapter 6 is about Michael Joyce, the author of Afternoon, the first hypertext fiction, and Storyspace, created by Joyce and Jay David Bolter.
Memory Machines will appeal to anyone who is curious about the history of computing in general and hypertext in particular. This book is highly recommended for computer science students and for students of history of science and technology, as well as for computing and engineering enthusiasts.
