---
title: "Memex"
chunk: 1/3
source: "https://en.wikipedia.org/wiki/Memex"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T04:36:58.676263+00:00"
instance: "kb-cron"
---

A memex (a portmanteau of "memory" and "index") is a hypothetical electromechanical device for interacting with microform documents and described in Vannevar Bush's 1945 article "As We May Think". Bush envisioned the memex as a device in which individuals would compress and store all of their books, records, and communications, "mechanized so that it may be consulted with exceeding speed and flexibility". The individual was supposed to use the memex as an automatic personal filing system, making the memex "an enlarged intimate supplement to his memory".
The concept of the memex influenced the development of early hypertext systems and personal knowledge base software. The hypothetical implementation depicted by Bush for the purpose of concrete illustration was based upon a document bookmark list of static microfilm pages and lacked a true hypertext system, where parts of pages would have internal structure beyond the common textual format.

== Development ==

=== An electromechanical memex device ===
In "As We May Think", Vannevar Bush describes a memex as an electromechanical device enabling individuals to develop and read a large self-contained research library, create and follow associative trails of links and personal annotations, and recall these trails at any time to share them with other researchers. This device would closely mimic the associative processes of the human mind, but it would be gifted with permanent recollection. As Bush writes, "Thus science may implement the ways in which man produces, stores, and consults the record of the race".
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. A memex would hypothetically read and write content on these microfilm reels, using electric photocells to read coded symbols recorded next to individual microfilm frames while the reels spun at high speed, stopping on command. The coded symbols would enable the memex to index, search, and link content to create and follow associative trails.
The top of the desk would have slanting translucent screens on which material could be projected for convenient reading. The top of the memex would have a transparent platen. When a longhand note, photograph, memoranda, or other things were placed on the platen, the depression of a lever would cause the item to be photographed onto the next blank space in a section of the memex film.
According to Bush, the memex could become "a sort of mechanized private file and library". The memex device as described by Bush "would use microfilm storage, dry photography, and analog computing to give postwar scholars access to a huge, indexed repository of knowledge any section of which could be called up with a few keystrokes."

=== Associative trails ===
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. At the time, Bush saw the current ways of indexing information as limiting and instead proposed a way to store information that was analogous to the mental association of the human brain: storing information with the capability of easy access at a later time using certain cues (in this case, a series of numbers as a code to retrieve data).

=== Other features ===
According to Bush, the memex would have features other than linking. The user could record new information on microfilm, 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." 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." 
In September 1945, Life magazine published an illustration by Alfred D. Crimi showing the "Memex desk". According to Life magazine, the Memex desk "would instantly bring files and material on an subject to the operator's fingertips". The mechanical core of the desk would also include "a mechanism which automatically photographs longhand notes, pictures and letters, then file them in the desk for future reference."

=== Extending, storing, and consulting the record of the species ===
Bush's 1945 "As We May Think" idea for the memex extended far beyond a mechanism that might augment the research of one individual working in isolation. In Bush's idea, the ability to connect, annotate, and share both published works and personal trails would profoundly change the process by which the "world's record" is created and used: