In the novel The City of Ember there are many themes including team work. Team work is a massive part of this story, the two main characters Doon Harrow and Lina Mayfleet work together and to complete a task never imaginable. They saved their dying soul and that is a huge accomplishment. In my opinion, the world wouldn't be together if the puzzle pieces didn't fit.
Another large theme in this story is determination because the 200 people that live in ember are courageous to survive the rough underground world. the main characters wouldn't have achieved the escape of Ember if they had no motivation."If you have proof, you have to pursue it!" the novel states on page
A third theme in the series the city of ember is hope. Hope is the one thing that keeps Doon and Lina believe ther is a way out. With the help of the hidden map they were persuaded to escape and find a way out into the real world.