The utterly charming prequel to the New York Times-bestseller Mr Penumbra's 24-hour Bookstore.San Francisco, 1969. The summer of drugs, music and a new age dawning. A young, earnest Ajax Penumbra has been given his first assignment as a Junior Acquisitions Officer - to find the single surviving copy of the Techne Tycheon, a mysterious volume that has brought and lost great fortune for anyone who has owned it. After a few weeks of rigorous hunting, Penumbra feels no closer to his goal than when he started. But late one night, after another day of dispiriting dead ends, he stumbles upon a 24-hour bookstore and the possibilities before him expand exponentially. With the help of his friend's homemade computer, an ancient map, a sunken ship and the vast shelves of the 24-hour bookstore, Ajax Penumbra might just find what he's seeking...

Robin Sloan grew up near Detroit and has worked at Poynter, Current TV and Twitter in jobs that have generally had'something to do with figuring out the future of media'. He has previously published short fiction in Kindle-only editions (Mr Penumbra started out as a 6000-word ebook). He lives in San Francisco. www.robinsloan.com / @robinsloan