It would become apparent to the visitors not too long afterward that personal computing would take a dramatic course correction away from typed machine instructions on a command line to a metaphorical desktop featuring a soap-bar-shaped “mouse” sending instructions to a bitmapped screen that had frames that resembled windows. Among the Apple visitors that day was cofounder Steve Jobs, who clearly recognized the power of this revolutionary interface.

The guide assigned by Xerox to demonstrate the system was Larry Tesler, a computer scientist who was a strong believer in the future of PCs as well as this new graphical user input (GUI) design. About the Apple contingent, he later told journalist Stephen Levy that “no other outsiders had so quickly grasped that a new paradigm in computing was operating at PARC.” Evidence of the impression that was made that day surfaced in Apple’s Lisa computer followed by the first Macintosh the company produced. According to Wikipedia, “Immediately after returning to Apple’s headquarters, (Jobs) set his team on creating a similar graphical user interface for their first product, the Apple Lisa.”


Larry Tesler passed away on Monday, February 17, 2020. Most obituaries noted that he was the inventor of the copy, cut, and paste and search/replace commands for PC text-writing programs. But those were only two of the items produced in Tesler’s long career directed by a singular principle: “When you think it’s as simple as it can be, there is probably a way to make it even simpler.”

This was more than a rule of thumb. In 1984, while working at Apple, Tesler published Tesler’s Law of Conservation of Complexity. “Every application has an inherent almost irreducible complexity. The only question is: who will have to deal with it—the user, the application developer, or the platform developer.” His answer, throughout his career, was design the machine for the user, not the engineers.

Silicon Valley’s Computer History Museum says Tesler “combined computer science training with a counterculture vision that computers should be for everyone.”


Looking over the stops along the way of Tesler’s career is like reviewing a timeline of the history of personal computing. From Xerox PARC to Apple, Amazon, Yahoo, and others, his contribution to the human/machine interface has been significant.

Stanford (1961-1964): Tesler entered Stanford University when he was 16, and he completed his degree in computer studies and mathematics in 1965. In the late ’60s, he worked at Stanford Artificial Intelligence Laboratory (SAIL). While there, he wrote a document compiler called Pub, which is recognized as one the first uses of markup language.

Xerox PARC (1973-1980): While at PARC, Tesler worked on many projects that furthered the research on GUI and WYSIWIG (“what you see is what you get” from screen image to print). He wrote the Gypsy word processor for the Office Systems Group and Smalltalk, the first dynamic object-oriented programming language. He also worked on one of the first portable computers, the Xerox NoteTaker. He was also responsible for the term “browser.”

Apple, Inc. (1980-1987): At Apple, he became Apple’s chief scientist, a post once held by the “other Steve”—Wozniak. There, according to his website, he “built and managed teams of up to 200 technologists and designers that contributed to such innovative products as the Lisa computer, Macintosh, Color QuickDraw, QuickTime, AppleScript, HyperCard, and Newton.”

Stagecast Software, Inc. (1997-2001): He cofounded the educational software company, which had two versions of a program that taught programming to children.

Amazon (2001-2005): He was hired as a vice president of engineering and was then promoted to vice president of shopping experience, where he worked on improving the website interface, including developing the book preview function.

Yahoo Inc. (2005-2008): Tesler served as vice president of Yahoo’s User Experience and Design Group.

23andMe, Inc. (2008-2009): Tesler took a position as internal consultant at the startup.

Larry Tesler may be remembered for specific inventions like the cut, copy, and paste functions, but his greatest contribution was his focus on eliminating complexity wherever it might appear between the user and their computer.

Andrew Liszewski, senior staff reporter for Gizmodo said of Tesler: “While there are undoubtedly countless other contributions Tesler made to modern computing as part of his work on teams at Xerox and Apple that may never come to light, his known contributions are immense. Tesler is one of the major reasons computers moved out of research centers and into homes.”

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