City of Ember, by Jeanne DuPrauRead about the other entries on the list.
Ember was built underground in order to spare mankind from a coming disaster. The problem is, 241 years after the city’s founding, the city is dying—its stores running low and its machinery failing—and no one remembers why they’re even down there in the first place. The secret set of instructions has been lost—or has it? Lina Mayfleet is a young woman whose baby sister uncovers the tattered documents that were intended to guide humans out of the city at the proper time. Reconstructing them with her friend Doon, Lina uncovers the history of Ember as well as a way to a promised future on the surface. But, because nothing is ever easy, she and Doon are declared fugitives by the greedy Mayor and forced to decide if they can save both themselves and the people of Ember itself.
--Marshal Zeringue