Mr. Penumbra’s 24-Hour Bookstore was written by Robin Sloan and published in 2012.

Synopsis

Set in San Francisco, unemployed twenty-something, Clay Jannon, finds work in a mysterious bookstore that rarely sells books and checks out encrypted texts to its members. With the help of friends at Google and in the startup community, Clay tries to unravel the mystery of the bookstore using data visualizations, natural language processing, and crowdsourcing.
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