Larry Tesler

Lawrence Gordon Tesler (April 24, 1945 – February 16, 2020) was an American computer scientist. He worked in the field of human–computer interaction. He had worked at Xerox PARC, Apple, Amazon and Yahoo!.
While at PARC, Tesler's work included Smalltalk, the first dynamic object-oriented programming language and Gypsy, the first word processor with a graphical user interface for the Xerox Alto. He also helped create the idea of copy and paste and the idea of modeless software.
Tesler was born in the Bronx, New York. He died on February 16, 2020 in Portola Valley, California of problems caused from a bike accident. He was 74.