In the novel The girl who owned a city by O.T.Nelson. What is the most important idea that the author wants you to consider?

This is largely a thematic question. I think that the power of ideas is an important theme. Lisa believes in the power of ideas. Good ideas can conquer any problem and bring amazing success. When Lisa is alone, she sits and thinks. When she is with her brother, she spends her nights thinking through problems, considering ideas, and planning for the future. She does the same thing when she is ruler of her own city. She spends time alone in her tower room, thinking by candlelight. Everything that Lisa gains, she gains by virtue of her thoughts and ideas. Everything that Lisa loses, she loses because she does not think and anticipate well enough.