Bradbury was always a cheerful book-signer, which accounts for the plethora of signed Bradbury books available online. He was also famously generous with his time, mentoring other writers, and encouraging young people to continue to write in the face of many obstacles.
Bradbury was born in Waukegan, Illinois in 1920 and published his first collection of short stories, "Dark Carnival" in 1947. In the early 1950s, Bradbury produced an astonishing succession of future classics: "The Martian Chronicles," (1950) "The Illustrated Man," (1951) and, of course, "Fahrenheit 451" (1953). The rest is history.
The bookish side of the Internet is quickly filling up with tributes to Bradbury, but if you are only going to read one essay on his life and work, check out Neil Gaiman's post on the Guardian's book blog. His touching tribute perfectly encapsulates the warmth of Bradbury's personality and the importance of Bradbury's work.
And for collectors, see Rebecca's post from earlier this week on "Death and Collectability," which discusses the tendency for demand to rise sharply in the wake of an author's death. For an overview of current rates for Bradbury books, and for some great images of his dust jacket covers, visit this post at the Abebooks blog, which includes the 15 most expensive copies of Bradbury currently available on their website.