The theme of this volume, the role of specific environments in cognitive development, has been central to my theorizing. Influenced by both Charles Darwin and James and Eleanor Gibson, my approach to action has always begun with an analysis of what Darwin preferred to call the “habits of life” of a species, and the evolutionary constraints on those habits. To use Gibsonian language, I have been interested in the evolution and develop­ ment of the ability to use those affordances of the environment that are basic to the fundamental human econiche. The use of these affordances reflects what Piaget would have considered a very sophisticated kind of biological regulatory process, in which both skill and knowledge become progressively adapted to a wide variety of behavioral contexts. This ontogenetic process of adaptation is intrinsically social — and here I follow Marx and Vygotsky, the fourth of my influences.