UNITED STATES—On July 26, William Kirk English died at the age of 91 in San Rafael, California. He was born in Lexington, Kentucky on January 27, 1929. He studied Electrical Engineering at the University of Kentucky before joining the United States Navy. In 1964, English left the Navy to become the first person to join the Augmentation Research Center (ARC) at the Stanford Research Institute (SRI).

The ARC was a research laboratory funded in 1963 by the United States Defense Department’s Advanced Research Project Agency (DARPA). The lab developed new technologies for information processing and was to be led by Douglas Engelbart, an American engineer and inventor listed as the co-inventor of the mouse.

According to Engelbart’s notes, “English built the initial prototype, and was its first user.”

On July 1965, English, Engelbart and Bonnie Huddart published a final report on the “Computer-Aided Display Control.” The report compared the mouse to various alternatives by “exploring methods of improving a person’s ability to compose and modify text presented on a computer-driven cathode ray tube display.”

On November 1970, SRI was awarded a patent for the mouse. It was named the “X-Y Position Indicator For A Display System.”

The New York Times reported that English is survived by his wife Roberta English, his two sons Aaron and John, and his stepdaughter Patricia.