This book explores how supportive relationships at all levels of an infant–family program (supervisor and staff, staff and family, parent and child) contribute to children's healthy social–emotional development (infant mental health). The authors present the core concepts of infant mental health, offer strategies that leaders and trainers can use to promote children’s mental health, and describe guidelines for referring very young children for assessment and treatment. This publication offers numerous vignettes featuring a mix of infant–family settings and exercises designed to help staff and leaders better understand and apply infant mental health practices.