John Bardeen (May 23, 1908 - January 30, 1991) was a physicist who was the co-inventor of the transistor. He developed a fundamental theory for conventional superconductivity together with Cooper and Schrieffer; today known as the BCS theory.
Bardeen was also an important advisor to the Xerox Corporation. Though quiet by nature, he took the rare step of urging Xerox executives to keep their California research center, Xerox PARC, afloat when the parent company was suspicious that its research center would amount to little.
Xerox PARC went on to create the point-and-click method, the mouse, and the laser printer, among other things.