In what has become a bad couple of months for computer science, John McCarthy, the father of artificial intelligence, died in late October at the age of 84.
McCarthy was a giant in the field of computer science and a seminal figure in artificial intelligence, defining the field for more than five decades. After studying at Caltech and Princeton, with brief professorships at Stanford and Dartmouth College, he went to MIT where he, along with his colleague Marvin Minsky, founded the MIT Artificial Intelligence Project. In 1962, he transferred to Stanford’s newly formed Department of Computer Science, where he founded and led the Stanford Artificial Intelligence Laboratory (SAIL). McCarthy was known for bringing scientific rigor to every aspect of life and for his wry, often self-deprecating sense of humor. This was best exemplified in a personal philosophy he termed “radical optimism” –- a positive outlook so strong that he said “Everything will be OK even if people don’t take my advice.“. Even by the end of his early days at MIT, he was already affectionately referred to as “Uncle John” by his students.
Most remarkable about his contributions are their diversity, their depth, and how they span both theory and practice: logical AI, advances in lambda calculus and the theory of computation, the Lisp programming language, garbage collection, design of the ALGOL programming language, popularising time-sharing, modern program verification (and with the benefit of hindsight it seems that he came remarkably close to denotational semantics), circumscription logic for non-monotonic reasoning and computer chess. He won the ACM Turing Award in 1971, the Kyoto Prize in 1988 and the US National Medal of Science in 1990.
There have been a huge number of excellent obituaries to John McCarthy, for example by SAIL, Stanford, CACM, The New York Times, The Guardian, as well as an excellent article in Nature by Vladimir Lifschitz. There is also much to be mined from his SAIL web pages.
As soon as it works, no one calls it AI any more.
John McCarthy (in response to the over-promises of AI in the late 1970s and early 1980s)
Digital, Data & Policy 
I can also highly recommend the recordings from the Celebration of John McCarthy’s Accomplishments event, held at Stanford in March 2012.
McCarthy was on point, when I read his paper on the epistemological problems in AI all I could think was “this man is SO DAMN CORRECT”. Here’s the paper: http://jmc.stanford.edu/articles/epistemological/epistemological.pdf