His was a remarkable life, full of genius, insight, inspiration, courage and intellectual creativity. His contributions during World War II (like the fact he broke the Nazi code and was privy to the information sent in secret messages to Hitler and his thugs even before they received it) may be directly responsible for saving hundreds of thousands of lives, and of accelerating the end of the war.
For all of his importance, however, his life was also very tragic. Because of the top-secret nature of his mathematical work during the war, he was never officially recognized. And to add insult to injury, his homosexuality was used to ban him from his own work, to treat him worse than a common criminal, and eventually it led to his suicide. This is his life:
For more on Turing's mathematical and philosophical importance, check out two of my favorite documentaries in this whole blog: Dangerous Knowledge with David Malone, and The Secret Life of Chaos with Jim Al-Khalili.