The rising population and industrial growth place increasing strains on a variety of material and energy resources. Understanding how to make the most economically and environmentally efficient use of materials will require an understanding of the flow of materials from the time a material is extracted through processing, manufacturing, use, and its ultimate destination as a waste or reusable resource. MaterialsCount examines the usefulness of creating and maintaining material flow accounts for developing sound public policy, evaluates the technical basis for material flows analysis, assesses the current state of material flows information, and discusses who should have institutional responsibility for collecting, maintaining, and providing access to additional data for material flow accounts.