Larry Tesler, an icon of early computing, has passed away. He was 74.
Tesler started working in Silicon Valley in the early 1960s, at a time when computers were inaccessible to the vast majority of people.
It was thanks to his innovations - which included the "cut", "copy" and "paste" commands - that the personal computer became simple to learn and use.
Xerox, where Tesler spent part of his career, paid tribute to him.
Tesler was born in the Bronx, New York, in 1945, and studied at Stanford University in California.
After graduating, he specialised in user interface design - that is, making computer systems more user-friendly.
He worked for a number of major tech firms during his long career. He started at Xerox Palo Alto Research Center (Parc), before Steve Jobs poached him for Apple, where he spent 17 years and rose to chief scientist.
After leaving Apple he set up an education start-up, and worked for brief periods at Amazon and Yahoo.
'A counterculture vision'
Possibly Tesler's most famous innovation, the cut and paste command, was reportedly based on the old method of editing in which people would physically cut portions of printed text and glue them elsewhere.
The command was incorporated in Apple's software on the Lisa computer in 1983, and the original Macintosh that was released the following year.
One of Tesler's firmest beliefs was that computer systems should stop using "modes", which were common in software design at the time.
"Modes" allow users to switch between functions on software and apps but make computers both time-consuming and complicated.
So strong was this belief that Tesler's website was called "nomodes.com", his Twitter handle was "@nomodes", and even his car's license plate was "No Modes".