"As We May Think" is a 1945 essay by Vannevar Bush which has been described as visionary and influential, anticipating many aspects of information society. It was first published in The Atlantic in July 1945 and republished in an abridged version in September 1945—before and after the atomic bombings of Hiroshima and Nagasaki. Bush expresses his concern for the direction of scientific efforts toward destruction, rather than understanding, and explicates a desire for a sort of collective memory machine with his concept of the memex that would make knowledge more accessible, believing that it would help fix these problems. Through this machine, Bush hoped to transform an information explosion into a knowledge explosion.

The article was a reworked and expanded version of Bush's essay "Mechanization and the Record" (1939). Here, he described a machine that would combine lower level technologies to achieve a higher level of organized knowledge (like human memory processes). Shortly after the publication of this essay, Bush coined the term "memex" in a letter written to the editor of Fortune magazine. That letter became the body of "As We May Think", which added only an introduction and conclusion. As described, Bush's memex was based on what was thought, at the time, to be advanced technology of the future: ultra high resolution microfilm reels, coupled to multiple screen viewers and cameras, by electromechanical controls. The memex, in essence, reflects a library of collective knowledge stored in a piece of machinery described in his essay as "a piece of furniture". The Atlantic publication of Bush's article was followed by an abridged version in the September 10, 1945, issue of Life magazine, accompanied by fanciful illustrations of the proposed memex desk and other devices Bush projected. Bush also discussed other technologies such as dry photography and microphotography where he elaborates on the potentialities of their future use. For example, Bush states in his essay that:

The combination of optical projection and photographic reduction is already producing some results in microfilm for scholarly purposes, and the potentialities are highly suggestive.

— Vannevar Bush

"As We May Think" predicted (to some extent) many kinds of technology invented after its publication, including hypertext, 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." Bush envisioned the ability to retrieve several articles or pictures on one screen, with the possibility of writing comments that could be stored and recalled together. He believed people would create links between related articles, thus mapping the thought process and path of each user and saving it for others to experience.

Bush's article also laid the foundation for new media. Doug Engelbart came across the essay shortly after its publication, and keeping the memex in mind, he began work that would eventually result in the invention of the mouse, the word processor, the hyperlink and concepts of new media for which these groundbreaking inventions were merely enabling technologies.

Since then, storage has greatly surpassed the level imagined by Vannevar Bush,

The Encyclopædia Britannica could be reduced to the volume of a matchbox. A library of a million volumes could be compressed into one end of a desk.