This doesn't happen to me very often, but there's been a few books I've stumbled upon that sort of consumed me until I'd read everything the author had ever written.
Mercedes Lackey was probably the first. I discovered her Valdemar books in high school in the 90s, and I think I spent most of my junior year tracking down and reading them all.
Dresden Files did the same thing, although there weren't many books published when I found Jim Butcher.
Most recently I found David Weber's Honor Harrington books, which were a blast although the series didn't really hold me all the way through. Given that there's a few dozen of them, I have a hard time feeling bothered.
by Onequestion0110