Infancy - which is defined as the period from birth to 18 months of age - is the single most critical stage in cognitive and socio-emotional development. Assembled under the auspices of the leading international organization in infant development - the World Association of Infant Mental Health - this reference offers a thorough interdisciplinary analysis of the biopsychosocial factors that impact upon normal and abnormal infant mental development. There are four separate volumes, available individually or as a complete set: Volume 1 - Perspectives on Infant Mental Health ; Volume 2 - Early Intervention, Evaluation, and Assessment ; Volume 3 - Parenting and Child Care ; and Volume 4 - Infant Mental Health Groups at High Risk .