This engaging book is a comprehensive exploration of children's happiness and success covering a wide range of factors influencing positive functioning. It offers a holistic view of children's well-being, identifying both threats and catalysts to happiness and success, as well as evidence-based strategies that promote optimal functioning. The first section of the book delves into the science of happiness, discussing the role of early social relationships, the importance of experiencing positive emotions and flow, spirituality, and physical health. The second section focuses on the science of success, exploring topics such as mindsets, self-control, and executive functions. Finally, the book explores individual and contextual factors explaining why character matters, the influence of media and technology, and the critical role of disadvantaged environments. Presenting happiness as an ongoing journey, intertwined with the pursuit and achievement of personal goals, the book concludes by proposing a new conceptual framework which identifies pivotal contributors to children's happiness and success such as relationships, self-regulation, and competence. Suited to upper-level undergraduate and graduate courses in child development, family studies, education, and positive psychology, this book is also an invaluable resource for caregivers, educators, and child practitioners. It is a must-read for anyone interested in cultivating a fulfilling, well-lived life for children and adolescents.