Book excerpt: Part of the authoritative four-volume reference that spans the entire field of child development and has set the standard against which all other scholarly references are compared. Updated and revised to reflect the new developments in the field, the Handbook of Child Psychology, Sixth Edition contains new chapters on such topics as spirituality, social understanding, and non-verbal communication. Volume 1: Theoretical Models of Human Development, edited by Richard M. Lerner, Tufts University, explores a variety of theoretical approaches, including life-span/life-course theories, socio-culture theories, structural theories, object-relations theories, and diversity and development theories. New chapters cover phenomenology and ecological systems theory, positive youth development, and religious and spiritual development.