Arthur C. Clarke 1917-2008
I was going to start this post by saying that I had read everything written by Arthur C. Clarke, but reviewing his oeuvre on Wikipedia, I realized that I had only scratched the surface. The man was not just a science fiction writer but a visionary; while many love his novels like Childhood's End (ever the urbanist, I preferred the City and the Stars) his solid non-fiction works like "The Promise of Space" inspired a generation.
He wrote in another era, one of incredible optimism, where science and technology would solve all of our problems. He solved a few of them himself, envisioning geosynchronous orbiting satellites in 1945. But he understood our tenuous position on this planet and described what would ultimately happen to us after we screwed up so badly in my absolute favourite short story written in 1949, History Lesson. Arthur C. Clarke, dead at 90. ::Washington Post