Book excerpt: The Handbook of Positive Psychology in Schools offers the most current and comprehensive insights into how positive psychology principles provide a framework for young people to become active agents in their own learning. The third edition of this groundbreaking volume assembles the latest global research identifying fundamental assets—hope, optimism, gratitude, self-efficacy, emotional regulation, among others—that support students’ learning and well-being. Chapters examining social-ecological perspectives on classroom quality and school climate provide best practice guidance on schoolwide policies and practices. These 35 new chapters explore positive psychology’s ongoing influence and advances on prevention, intervention, and assessment practices in schools.