For those who, like me, never heard of him before, a Wikipedia summary:
He is best known for his work on the challenges of human–computer interaction, particularly while at his Augmentation Research Center Lab in SRI International, resulting in the invention of the computer mouse, and the development of hypertext, networked computers, and precursors to graphical user interfaces.
For those who, like me, never heard of him before, a Wikipedia summary:
The mother of all demos.