For centuries, poets and philosophers extolled the benefits of a walk in the woods: Beethoven drew inspiration from rocks and trees; Wordsworth composed while walking over the heath; Nikola Tesla conceived the electric motor while visiting a park. From forest paths in Korea to islands in Finland to eucalyptus groves in California, Florence Williams investigates the science at the confluence of environment, mood, health and creativity. Delving into new research, she uncovers the powers of the natural world to improve health, promote reflection and innovation, and strengthen our relationships. As our lives shift indoors, these ideas—and the answers they yield—are more urgent than ever.