This study examines in detail relations between the states and the roles of United States Congress and Supreme Court in determining the nature of such relations - a distinguishing characteristic of a federal system. The neglect of interstate relations by scholars is surprising in view of the long and ongoing struggle between state power and federal power in the US. This new text provides a comprehensive examination of interstate relations, with up-to-date information and analysis relative to interstate suits, full faith and credit, priveleges and immunities, tax exportation by states, interstate business competition, and interstate trade barriers. In addition , the work proposes a new model for improving interstate relations in the US. This important text will be of interest to scholars and students in American government and politics, state government and politics, and intergovernmental relations.