People have concepts^—^mental representations^—^of the individual physical objects that surround them: representations of their best friends, family pets, keepsakes, mementos, and countless others. We follow some of these things over long periods, including times when we do not perceive them. We believe these items are structured through the parts and substances that compose them: organisms by their body parts, artifacts by their mechanical parts. Taking Shape aims to understand the nature of these individual concepts, especially how they enable us to identify objects we have seen before and to think about their composition. Surprisingly, it is the first book in cognitive psychology that is devoted to our concepts of individual things (singular concepts), since most work on concepts has concerned concepts of whole categories, such as the category of people or pets. This book proposes that object concepts depend on attributing a causal structure to things, a set of physical forces that shape and maintain them. The theory casts a new perspective on a wide range of traditional problems in cognitive science, including object perception, recognition memory, categorization, pronoun resolution, and intuitive physics. It also draws on philosophical and linguistic theories of reference and metaphysics, attempting to capture which aspects of these theories mesh with our intuitive ones.