Primary care pediatric health care clinicians can integrate basic principles and strategies of the field of infant mental health within the time constraints of their current practice, while advocating for additional resources to support the expansion of the preventive potential afforded by new scientific advances in this field. Infant mental health is a relatively young field with the potential to reduce human suffering and health care costs associated with early-onset developmental, emotional, and behavioral disorders. This will depend not only on primary care pediatric diagnostic acumen, but also on related investments in health care preventive screenings and interventions, training and infrastructure, as well as community supports. The health and development of infants, young children, and families emerge from the interactions of a wide range of factors—including health, education, and economic policy, as well as attributes of local communities and the larger physical environment—and impact economics and security at national and global levels. [Copyright &y& Elsevier]