Plot Summary: "The City of Ember" by Jeanne DuPrau is a dystopian novel set in the underground city of Ember, which was constructed by a coalition of architects, scientists, and doctors known as the Builders. The city was built to ensure humanity's survival during a series of apocalyptic events known as the Disaster, with the intention that future generations would not know about the outside world or that they lived underground. The Builders planned for the city to last for two centuries, after which the citizens would evacuate and return to the surface world. However, the seventh mayor, who was Lina's great-great-grandfather, took the box containing the exit instructions home and tried to break it open, thinking it might contain a cure for a deadly coughing disease. He died before returning the box, and it was lost until Lina's baby sister, Poppy, found it and tore up the papers inside.

The story follows two young protagonists, Lina Mayfleet and Doon Harrow, who are assigned jobs by lottery at their graduation ceremony. Lina is assigned to be a "Pipeworks Laborer," and Doon is assigned to be a "Messenger." They exchange their assignments and begin work in their respective positions. As they delve deeper into the city's problems, they discover that the seventh mayor's actions have led to the loss of the exit instructions. They decide to reveal the truth and escape the city, leaving a note for others to follow.

Key Themes:

1. Survival and Adaptation: The novel explores how the inhabitants of Ember adapt to their underground environment and the challenges they face.
2. Ignorance and Knowledge: The Builders' intention to keep future generations ignorant of the outside world is a central theme, highlighting the importance of knowledge and understanding.
3. Corruption and Power: The seventh mayor's actions and the subsequent corruption in Ember's leadership are significant themes, illustrating how power can be misused.
4. Hope and Resilience: Despite the dire circumstances, Lina and Doon's determination to escape and reveal the truth symbolizes hope and resilience in the face of adversity.

Critical Reception: "The City of Ember" has received generally positive reviews for its engaging storyline and thought-provoking themes. Critics have praised the book for its ability to create a vivid and immersive world, while also addressing complex issues like survival, knowledge, and power.

The book has been praised for its unique premise and the way it explores the consequences of a society built on secrecy and ignorance. However, some critics have noted that the characters, while likable, are somewhat one-dimensional and that the plot could be more complex.

Overall, "The City of Ember" is a compelling and thought-provoking novel that has captured the imagination of readers with its blend of adventure, mystery, and dystopian themes.