Ajax Penumbra 1969 is a prequel to Robin Sloan's novel Mr. Penumbra's 24-Hour Book, which became a bestseller in dozens of countries around the world. The secret society "Festina Lente" is looking for the secret of immortality. This is the type of knowledge that you want to gain during your lifetime, while other matters can be postponed until later. In August 1969, young Ajax Penumbra comes to San Francisco in search of the only copy of an ancient book lost almost a hundred years ago. The book, if it did not burn in a fire and did not crumble into wood dust, has been predicting destinies for several centuries. The book shows Penumbra the right turn, and around the turn...a round-the-clock bookstore.