This volume contains 12 studies on political, social, economic, and religious aspects of the history of Central Asia and Iran in the period from the fourth century B.C.E. to the fifth century C.E. by leading specialists in the field. They interpret and reconstructing the region's past based on various kinds of evidence, including literary, archaeological, linguistic, and numismatic. Some papers present the findings of recent archaeological excavations in Old Nisa and Uzbekistan for the first time.