For almost 2000 years, an essential chapter in the history of China was missing. The second and first centuries B.C. were a critical period - they saw the birth and development of the new Chinese Empire and its earliest expansion and acquisition of frontier territories. In the last century, however, about 60,000 of Han-period documents have been discovered in Central Asia and Western China, preserved on strips of wood and bamboo. Through Chang's translation of these documents, and his subsequent analysis and examination, new light is shed on the public and private lives of those who lived in the frontier regions. His study enables a clearer understanding of the origins and development of the concepts of state, nation, nationalism, imperialism, ethnicity, and Chineseness. Chang also explores the formation and growth of the Chinese Empire and its changing national identity, and considers the impact of early nation-building and later territorial expansion, offering the first systematic reconstruction of the history of Chinese acquisition and colonization.