Nora Newcombe and Janellen Huttenlocher argue for an interactionist approach to spatial development that incorporates and integrates essential insights of the classic three approaches. They show how biological preparedness interacts with the spatial environment that infants encounter after birth to create spatial development and mature spatial competence. Topics covered include spatial coding during infancy and childhood; the early origins of coding distance in continuous space, of coding location with respect to distal external landmarks, and of hierarchical combination of information; the mental processes that operate on stored spatial information; spatial information as encoded in models and maps; and spatial information as encoded in language.