"The Overstory" is a novel by Richard Powers that intertwines the lives of multiple characters, each connected to trees and nature in different ways. The story explores themes of environmentalism, the interconnectedness of life, and the impact of human actions on the planet. Throughout the narrative, characters like Nick Hoel and Patricia Westerford experience personal transformations that lead them to advocate for the protection of forests. The book emphasizes the importance of trees, illustrating their roles in ecosystems and the profound relationships humans can have with the natural world.