Larry Tesler obituary

Anyone who uses the cut, copy and paste commands on their computer or mobile device has Larry Tesler to thank for making them so simple and easy to use. Tesler, who has died aged 74, began his work on cut, copy and paste in 1973, when he was hired by Xerox's Palo Alto Research Center (Parc) in California. Among other things he worked with a fellow computer scientist, Tim Mott, on the development of Gypsy, a "modeless" word processor. At the time most software had modes: for example, you might press I to enter the insert mode, or R for the replace mode. But Tesler's research showed that non-expert users found modes confusing – and so he began to fight against them.