Douglas C. Engelbart, the inventor of the computer mouse, died this week at the age of 88. He patented his simple but highly innovative invention, called an “X-Y Position Indicator for a Display System”, in 1970. (US 3541541) Engelbart’s invention helped launch the age of the personal computer. Millions of mice are produced each year. Engelbart’s mouse patent has been cited in 137 patents. The CPC classification for computer mice is G06F3/03543.