Jeanne DuPrau

When a roamer trades them an ancient book with only a few pages remaining, Lina and Doon return to Ember to seek the machine the book seems to describe in hopes that it will get their new community, Sparks, through the winter.

A modern-day classic. This highly acclaimed adventure series about two friends desperate to save their doomed city has captivated kids and teachers alike for almost fifteen years and has sold over 3.5  MILLION copies!
 
Lina and Doon have led the citizens of Ember to an exciting new world. When they discover a village called Sparks, they are welcomed, fed, and given places to sleep. But the town’s resources are limited...

Several hundred years in the future, in a world where fossil fuels are no longer used as a power source, a thirteen-year-old boy named Keith joins a jet pack project that will give people the ability to fly.

For centuries, the residents of the underground City of Ember have flourished in an amazing world of glittering lights and quiet contentment. But when the City's massive power generator begins to fail, the streetlamps fade - along with the hopes of the townspeople. Now it will be up to two courageous teenagers to follow a trail of clues left by the ancient builders to find the way out of Ember before their world is plunged into complete darkness.