September 4, 1927 – October 23, 2011
Famous Artificial Intelligence researcher and Computer Science theorist.
www.edge.org
His web site: www-formal.stanford.edu 
I hardly can begin to describe such a person, one of my personal heroes.
John Mc Carthy "invented" the Lisp Language; he first started thinking about it in 1956. He figured out what he wanted, and started doing it, with some help from some friends. It's gotten away from him, since about 1962, but he was still the major starting force.
He was at MIT at the time, and now is a Professor of Computer Science at Stanford. -- He left for Stanford in 1962 and has been there since; he's now an emeritus. From 1965 to 1980 he directed the Stanford AI Lab, so he was a leading figure in two of the Great Research Labs from the heyday of AI research.
During his time at MIT he was one of the first to propose time-sharing operating systems, leading to the creation of the Compatible Time Sharing System. He also coined the term "Artificial Intelligence''".
Here's a good paper about John Mc Carthy's influence on Lisp Language:
Here's a (rather silly) picture:
He seems to be a person who has humility, humor, and good sense about him. But maybe that's just my impression.
It's not just you; he is consistently like that in person. -- Doug Merritt
Recipient of 1971 Turing Award.
See also Implementing Lisp
See original on c2.com