I can't really write an obituary for Michael Hart. I'll point you to the words of those who knew him in describing the man and his life.
I can tell you this: as the inventor of the e-book and the founder of Project Gutenberg, Michael Hart had a profoundly important vision for the future of literacy, literature, learning, sharing. Project Gutenberg is the oldest digital library, with some 36,000 titles freely and openly available for anyone to download and read. Sherlock Holmes, Ulysses, Pride and Prejudice e-books. Free. As Hart said, "One thing about eBooks that most people haven't thought much is that eBooks are the very first thing that we're all able to have as much as we want other than air. Think about that for a moment and you realize we are in the right job."
GlueJar's Eric Hellman has made a wonderful suggestion, I think, that we honor the life and work of Michael Hart by donating something to the public domain. He offered his PhD dissertation. I'm adding my Master's Thesis in Folklore to the public domain. (I'll link it once I have the info -- a big thanks to John Russell from the UO Library in that effort!)
That means you can take what I think is quite a wonderful exploration of the storytelling and performance of political pranks and remix it, adapt it, write a screenplay, make a movie, build a video game, build an app, teach a class, make a ton of money, prove folks wrong about the value of a humanities education and so on. Go for it. Thanks to the public domain and the technology of Michael Hart, you can.