This book traces how naturalism—the idea of a common theory uniting natural social systems—has contributed to major shifts in urban planning. Beginning in the 17th century, when the human body began to emerge as an inspiration for urban planning, the book examines the work of medical analyses of city life. Responding to the 19th century industrial revolution and 20th century modernism, the Second World War and mass motorisation, Dr Marco Amati shows how vitalism, eugenics, evolutionary theories and medical treatments were applied to understand cities and propose new urban forms. While critically evaluating the uses of naturalism, Amati also observes a renewed interest in the application of sciences to analyse city life, arguing that this is essential to help resolve challenges of human-induced climate change.