Primary medical providers for children know and love their patients most intimately. As they treat the body, they observe the complex emotional development and challenges of the children under their care and their families. These providers need a trusted guide to help them understand the mental health aspects of their work and to provide precise and effective interventions. Here is that guide. A pediatrician and child psychiatrist with four decades of primary care experience designed this guide to furnish exactly what the primary provider needs. It belongs in every primary care office, next to the otoscope and stethoscope. It delivers expert practical understanding of emotional issues that belong in primary care. It expresses these insights free of jargon. It proposes ways of talking with children and parents about these matters. The guide reviews the practical aspects of emotional development from birth through adolescence. It addresses both the many of the chronic medical challenges treated by primary providers, and the social and familial challenges of the 21st century. Finally, it discusses self-care for the beleaguered provider.