Keynote: This 4-volume set offers comprehensive coverage of children's psychological development during the critical early years of life. Infancy—which is defined as the period from birth to 18 months of age—is the single most critical stage in cognitive and socioemotional development. The comprehensive WAIMH Handbook of Infant Mental Health offers the first thorough interdisciplinary analysis of the biopsychosocial factors that impact normal and abnormal infant mental development. Assembled under the auspices of the leading international organization in infant development—the World Association of Infant Mental Health—this ground-breaking four-volume reference offers a state-of-the-art overview of the field by the world's leading researchers, clinicians, and scholars.