“When the history books of the future are written, Alan Turing will go down in the company of Newton and Darwin and Einstein. His visions changed how humanity conceives of computation, information and pattern — and 100 years after his birthday, and 58 years after his tragic death, Turing’s legacy is alive and growing.” That’s from the Wired.com article celebrating Turing’s 100th birth anniversary who was born 23rd June, 1912.
Anyone who has studied the theory of computation knows about Alan Turing. I still remember what I had learned about cellular automata , the halting problem, Turing machines and the Turing test, Universal Turing Machines (UTM) and other fascinating ideas.
The outcome of the second world war could have been different if it had not been for the genius of Turing. The Wired article says:
In a tour-de-force of logic, information theory and sheer insight, Turing designed the machines that by summer 1940 allowed Allied forces to decipher German communications. Winston Churchill would later describe it as the single largest contribution to Allied victory. Without it, the war may have had a different ending.
. . .
Often called the father of computer science, Turing’s 1936 paper “On Computable Numbers, with an Application to the Entscheidungsproblem,” articulated ideas that became technological bedrock: that any computable problem could be computed on a machine, with calculations controlled by means of encoded instructions; and that code, rather than machine, was the essence of a computer.
Turing was an extraordinary human being. His parents lived in India for a while. But for all his contributions to the world, he was hounded by the English for being gay. He was chemically castrated — the alternative was prison. He committed suicide a little before this 42nd birthday.
I am sure that England is very proud of him today. But they killed him. Samuel Johnson (1709-1784), the great lexicographer, could have been talking about Turing when he wrote,
See nations slowly wise, and meanly just,
To buried merit raise the tardy bust. 
Happy Birthday, Alan!
Post Script: Read this beautiful essay “‘A Perfect and Beautiful Machine’: What Darwin’s Theory of Evolution Reveals About Artificial Intelligence” by Daniel Dennett in The Atlantic June 22, 2012. (Hat tip: A Tiku.)
 Just the other day I was telling a friend about John Conway’s “The Game of Life.” It was one of the first programs that I had written.
 The wiki notes that while Turing was born in London, he was conceived in India. His father was in the Indian Civil Services, which was renamed the Indian Administrative Services after India’s political independence from Britain.
 From “The Vanity of Human Wishes” (1749) by Dr Samuel Johnson.