Silo is a dystopian science fiction series by American author Hugh Howey, which began in 2011 as the self-published short story Wool and expanded into the foundational novels Wool (2011), Shift (2013), and Dust (2013). In March 2013, Howey secured a high-profile print-only deal with Simon & Schuster for approximately $500,000, famously declining seven-figure offers from publishers to retain the lucrative digital rights he'd built through Kindle Direct Publishing. Set on a toxic, post-apocalyptic Earth, the plot centers on humanity inhabiting a self-sustaining 144-floor underground Silo, where anyone who expresses a desire to go outside is sentenced to "cleaning" the external sensors—a fatal task meant to prove the outside is uninhabitable. A key twist occurs when Sheriff Holston, sent to clean, initially sees a vibrant world through his protective suit's visor, only to discover it's a computer-generated simulation masking a truly lethal environment, which leads to his death and opens the door for mechanic Juliette Nichols to become a protagonist. The blockbuster series spawned a graphic novel and the Apple TV+ television adaptation, and Howey has confirmed plans for a future trilogy set in Silo 40.