The book "The Developmental Science of Early Childhood" offers a comprehensive introduction to the field of early childhood development, known as "infant mental health." It integrates current research findings from developmental psychology, genetics, and neuroscience, and presents a model for prevention, intervention, and treatment that extends beyond the early years of life. Readers are provided with an accessible guide that applies the core concepts of this dynamic discipline to common childhood issues such as attention deficits, anxiety disorders, and sleep disturbances. The first part of the book provides an overview of the key research areas and theories to establish a solid knowledge base that enables professionals to integrate the principles of this comprehensive discipline into their clinical practice. The second part explores the remarkable applications of these concepts in clinical work, addressing topics such as gathering an early developmental history, managing postpartum depression, and treating sleep problems from the perspective of early childhood mental health.