His website (harryharrison.com) is reporting that that he passed away yesterday from unknown causes.
He was one of my favorite authors simply because, while he was broadly a Scifi writer, his body of work was so eclectic. Personally, I'll always have a soft spot for The Stainless Steel Rat and Bill, the Galactic Hero, but I also fondly remember The Deathworld Trilogy, which was as dark as the first two were light. I guess I'll be reading some Harrison during sustained silent reading in my classes for the next few weeks.
Ad Astra, Mr. Harrison.
Vocatus atque non vocatus, Deus aderit. -- Erasmus
All others things being equal, the simplest solution is usually stupidity. -- Darwin Minor
When I lived in Tampa, he seemed to be at every single fandom convention that was held there. He was always super nice and would happily draw you something without even charging, unlike most artists today.