Clay Jannon, web designer turned bookstore clerk, breaks up his night-shift boredom by tracking the reading patterns of his employer's more eccentric customers. A peek at what they most frequently “borrow” reveals coded books unavailable anywhere online. This discovery poses the perfect challenge for Clay's ambitious network of friends—a nerdy set of avengers eager to investigate the convoluted secrets Mr. Penumbra hides in (and beyond!) his quirky bookstore. Throughout this dazzling novel, Robin Sloan seamlessly interweaves a smorgasbord of subjects, including the printing industry, museum science, Google, thievery, and a 500-year-old fellowship. While readers might be intrigued by the classic concept of a book about books, this thrilling story goes beyond celebrating a love for the page; it emphasizes that the connection of sharing stories is one constant factor in a rapidly changing world. A Reader Review by Michele Dobbins of Tallahassee, Florida