This excerpt from James Clear's Atomic Habits explains the science of habit formation, focusing on how small changes compound over time to produce significant results. The book details a four-step model for habit creation (cue, craving, response, reward) and emphasizes the importance of system over goals, identity-based change, and environmental design in shaping behavior. Clear also addresses challenges like delayed gratification and boredom, offering practical strategies and real-world examples to improve habits in various aspects of life.