This competition expands NSF support of the Human and Social Dynamics Priority Area building on the FY 2003 HSD Special Competition. The HSD priority area promotes a comprehensive multi-disciplinary approach to understanding human and social dynamics that will significantly advance the scientific understanding of human action and development at the micro level, and of human adaptation and change at the organizational and societal levels. Six areas of emphasis are highlighted. Three topical areas of substantive concern are agents of change, the dynamics of human behavior and decision-making and risk. Three resource related areas designed to expand the nation's scientific capacity to understand the complexities of human behavior are spatial social science, modeling and infrastructure development. The HSD priority area will extend for five years.