This introductory section of the book lays the theoretical and empirical foundations for the adoption of a population-based approach to parenting support that incorporates promotion, prevention, and treatment activities into one comprehensive multilevel system of intervention. An empirically supported system of parenting support incorporates knowledge of the role of parenting in influencing the course of human development. The system integrates principles and techniques of positive parenting, behavioral, cognitive, and affective change with principles and techniques derived from the broader field of public health intervention. This introductory section of the book makes the case for the importance of parenting programs that tackle all three domains if children’s developmental and mental health outcomes are to be substantially improved. The Triple P—Positive Parenting Program is a multilevel system of parenting support that recognizes this importance.