Shape is a fundamental construct in cognitive development in and beyond geometry. For example, young children form artifact categories characterized by similarity among instances in shape (Jones & Smith, 2002). Even very young children show strong biases to attend to fine-grained shape when learning novel object names, at least when directed to a rigid object. We begin by extending the arguments that opened Chapter 7 concerning the importance of geometric and spatial thinking. Then we introduce several theoretical perspectives on children's development of shape concepts, followed by our own hierarchic interactionist position that we believe is most consistent with existing evidence.