Mr. Penumbra's 24-Hour Bookstore, written by Robin Sloan, was published in 2012. This takes place in a San Francisco, and the main character is Clay Jannon.
Clay know technology, but he works in a bookstore where the customers don't even buy many books. Clay decides there is something weird behind the bookstore. The customers usually only borrow a series of books that don't have any words-they only have grids of numbers. After watching these customers for a long time, Clay decides to convince some of his other technology-loving friends to try to decipher the code. Penumbra, who is the owner of the bookstore, is intent on solving what this book is trying to say.
This book is Sloan's first novel, and it originated from a story in Sloan's website. This book combines many elements of books such as mystery, frienship, and fantasy, and it is celebrated as one of the top 100 books in the San Francisco Chronicle in 2012.