Wool by Hugh Howey (2013)

The outside is toxic and deadly. For generations, humankind has been confined to a massive underground silo. Everyone must serve a purpose and are tightly regulated to make sure nothing goes to waste. Step outside of the law, and you are sentenced to death by "cleaning" – sent outside with a suit designed to keep you alive only long enough to clean the exterior landscape cameras. Why all those sentenced actually go through with the cleaning is a mystery to those in the silo....

Juliette, a young woman from the mechanical division, is handpicked to become the next sheriff after the last one volunteered to clean. As she becomes acclimated to her new position, Juliette starts piecing together information that makes her question the purpose and motives of the Silo's leaders – information that could get her sentenced to clean in a heartbeat. Hugh Howey's suspenseful post-apocalyptic novel pulls the reader into the world of the Silo and precariously holds them right at the tip between order and chaos. The first in a trilogy, Wool will leave you scrambling for the next installment.