I've been mildly obsessed with the novels of Nevil Shute for the past three years, and have finally completed my collection of his books -- 25 volumes in all, including an autobiography. I still have two books left to read, and they're lined up at the end of my Shute Shelf. The unread books are both old editions from the 50's, and have that pleasant library/grandma's attic smell to them.
This is not the first time I've read every book by a given author -- I had a Michael Crichton phase in high school, followed by an Arthur C. Clarke phase (I didn't read everything, but close). Prior to high school, I'm pretty sure I read everything Cynthia Voigt ever wrote. After college I discovered and devoured Neal Stephenson's work (including the Stephen Bury books).
Anyway, it took me years to track down all the Nevil Shute volumes, and I feel a certain completist satisfaction in seeing them all together on a shelf. When I finish the last one, I'm considering going back and reading them over, chronologically (I hear you get bonus nerd points for doing that). Shute's books are pretty similar in their details: there's generally some sort of challenge that necessitates a long journey, a lot of technical material concerning airplanes and boats, and some sort of wartime romance. Despite this similarity of theme (or perhaps because of it), I still enjoy each volume, and reading so much by a single author has taught me something about writing -- I can see him experimenting with technique, and I can see his style evolve over time. I'm even considering going to a meetup sponsored by the Nevil Shute Norway Foundation -- thus solidifying my status as a superfan.
Anyway, all this got me thinking: which authors have inspired you to read all their work? And yeah, I suppose J.K. Rowling counts.