Many of the key challenges and opportunities in the study of matter involve complex and collective phenomena in which many parts exhibit organization without a central instruction set or clock. At the core of this enterprise in the study of matter is the search for an understanding of “emergent behavior”—that is, phenomena whose ultimate cause involves interactions between many simple units but which cannot be easily predicted from knowledge of the component parts alone. Examples of emergence are ordered convection cells in fluids, metabolic processes in cells, cognition, and stripes in superconductors. Our shorthand designation for soft, hard, and living matter exhibiting emergent behavior is “complex adaptive matter.”