Psychology is caught in a conflict of paradigms. We all claim to be interactionists, yet we continue to accept the language and the thinking of traditional dichotomies: nature/nurture, innate/learned, mind/body, organism/environment. This clear and refreshingly-written authoritative text explores these confusions and moves on to offer an alternative view of development, first describing in an accessible way ecological and dynamic systems perspectives and then combining them to provide a more coherent and powerful critique of recent research and major issues.