Nearly five years ago, I met perhaps the most well-versed geek I've ever known. His knowledge of not just popular culture but the storied foundations of the science fiction and fantasy genres put me to shame. It made me realize that, in my consumption of the latest Star Trek and Forgotten Realms novels, I'd never made time to expose myself to the classics.

I've slowly been trying to rectify that over the past few years, during which time I've read Dune, Foundation, Discworld, Ringworld, Ender's Game, I Am Legend, and Game of Thrones (before it was a television series). My current assignment is The Left Hand of Darkness, after which I know there are many more books yet to read. But rather than scraping the bottom of the barrel, I instead find myself with the opposite problem: with so many good books to read, which do I tackle next?

NPR has the answer. This summer, they invited readers and listeners to submit their favorite fantasy and science-fiction novels for consideration as the best of all time. Five-thousand submissions, 60,000 votes, and 237 semi-finalists later, they presented the final list of the top one-hundred books (and on a single, unpaginated page, at that!).

Of the top ten books, I've read six; I'm embarrassed to say it was only half that before adding the titles I earlier listed. Altogether, only 23% of the books have crossed my reading list. I still have much work to do. But how to choose from the remaining 77, other than haphazardly?

Unsurprisingly, geeks who like fantasy, sci-fi, and NPR also like flowcharts. has created a comprehensive visual guide to selecting your next novel. By asking yourself some simple questions, such as "Enjoy quests to prevent great evil from conquering the world?" or "Robots or martians?", you can quickly lead yourself to the genre, topic, series, or allegory of your liking.

Using this flowchart, I've determined that my next three sci-fi novels should be Neal Stephenson's Cryptonomicon, Timothy Zahn's Star Wars: The Thrawn Trilogy, and Arthur C. Clarke's Childhood's End; in the fantasy realm, I'll be looking at T.H. White's The Once and Future King, Neil Gaiman's American Gods, and Susanna Clarke's Jonathan Strange & Mrs. Norrell. At least one book in each genre is already in my personal library, sitting in my "to-read" pile for years now. That seems as good a place to start as any.

What sci-fi and fantasy novels are on your list?

(Hat tips to Michele and Barbara)