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The "memex" (a portmanteau of "memory extender") is the name given by Vannevar Bush to the theoretical proto-hypertext computer system he proposed in his 1945 The Atlantic Monthly article "As We May Think". The memex has influenced the development of subsequential hypertext and intellect augmenting computer systems.

Contents 1 Details 1.1 A Proto-Hypertext System 1.2 Associative Trails 1.3 Other Features 1.4 Missing Features: Search and Metadata 2 Criticism 3 Legacy 4 See also 5 References 6 External links

Bush described the device as electronically linked to a library and able to display books and films from the library and automatically follow cross-references from one work to another.

The memex not only offered linked information to a user, but was also a tool for establishing the links. The technology used would have been a combination of electromechanical controls and microfilm cameras and readers, all integrated into a large desk. Most of the microfilm library would have been contained within the desk, but the user could add or remove microfilm reels at will.

The technology of the memex is often confused with that of hypertext. Although Bush's idea inspired the creation of hypertext, it is not considered to be hypertext. The memex as proposed by Bush could create links between a pair of microfilm frames, but it could not create links in the modern sense where a hyperlink can be based on a single word, phrase or picture within a document.

Furthermore, Bush's notion of associative trails has generally not been implemented in the vast majority of hypertext systems. An associative trail as conceived by Bush would be a way to create a new "linear" sequence of microfilm frames across any arbitrary sequence of microfilm frames by creating a chained sequence of links in the way just described, along with personal comments and "side trails". The closest analogy with the modern Web browser would be to create a list of bookmarks pointing to articles relevant to a topic, and then to have some mechanism for automatically scrolling through the articles (for example, use Google to search for a keyword, obtain a list of matches, and then use "open in new tab" in your browser and visit each tab sequentially). Modern hypertext systems with word and phrase-level linking offer more sophistication in connecting relevant information, but until the rise of wiki and other social software models, modern hypertext systems have rarely followed Bush in providing individuals with the ability to create personal trails and share them with colleagues - or publish them widely.

The memex also had other features; the user could generate new information on microfilm, such as by taking photos from paper or from a touch-sensitive translucent screen. A user could ".. insert a comment of his own, either linking it into the main trail or joining it by a side trail to a particular item. ... Thus he builds a trail of his interest through the maze of materials available to him" (AWMT). A user could also create a copy of an interesting trail (containing references and personal annotations) and "... pass it to his friend for insertion in his own memex, there to be linked into the more general trail" (AWMT). As observers like Tim Oren have pointed out, the memex could be considered to be a microfilm-based precursor to the personal computer. The September 10, 1945 Life magazine article showed the first illustrations of what the memex desk could look like, as well as illustrations of a head-mounted camera, which a scientist could wear while doing experiments, and a typewriter capable of voice recognition and of reading text by speech synthesis. Taken together, these memex machines were probably the earliest practical description of what we would call today the Office of the future.

The system had no automatic search, nor a universal metadata scheme such as a standard library classification or a hypertext element set like the Dublin core. Instead, when the user made an entry, such as a new or annotated manuscript, typescript or image, he was expected to index and describe it in his personal code book. By consulting his code book, the user could retrace annotated and generated entries.

Michael Buckland suggested the memex was severely flawed because Bush did not thoroughly understand information science, nor microfilm^[1]. Buckland also criticizes Bush for inadequate research. Bush did not mention either the related microfilm based workstation proposed by Leonard Townsend in 1938 or the more detailed microfilm and electronics based selector, patented by Emmanuel Goldberg in 1931.

This idea directly influenced computer pioneers J.C.R. Licklider (see his 1960 paper Man-Computer Symbiosis), Douglas Engelbart (see his 1962 report Augmenting Human Intellect), and also led to Ted Nelson's groundbreaking work in concepts of hypermedia and hypertext.^[2]

As We May Think also predicted many kinds of technology invented after its publication in addition to hypertext such as personal computers, the Internet, the World Wide Web, speech recognition, and online encyclopedias such as Wikipedia: "Wholly new forms of encyclopedias will appear, ready-made with a mesh of associative trails running through them, ready to be dropped into the memex and there amplified."

Vannevar's influence is still evident in research laboratories of today in both Gordon Bell's project, MyLifeBits (from Microsoft Research) as well as Richard Furuta and Frank Shipman's Walden's Paths project (from Texas A&M University). Both projects have implemented path-based systems reminiscent of the Memex.

• People: Vannevar Bush, Douglas Engelbart, J.C.R. Licklider, Ted Nelson
• Ideas: external memory, hypermedia, hypertext, intelligence amplification, office of the future

1. ^ Buckland, Michael K. "Emanuel Goldberg, Electronic Document Retrieval, And Vannevar Bush's Memex". Journal of the American Society for Information Science 43, no. 4 (May 1992): 284–294
2. ^ Engines of Creation (1986) by K. Eric Drexler.

• "As We May Think" - The original article from the Atlantic Monthly archives
• "As We May Think - A Celebration of Vannevar Bush's 1945 Vision", at Brown University

	Preceding:	As We May Think
	Subsequent:	Project Xanadu