My aim in writing this book has not been to add another History of the Roman Empire to those which already exist. My purpose is more modest and much more limited. We possess very good surveys of the foreign policy of the Roman Emperors, of the constitutional history of the Roman Empire, of the system of administration, both civil and military, and of the organization of the army. Valuable work has been done in describing the municipal life of Italy and of some of the provinces, and attempts have been made to present complete pictures of the historical development of some of the provincial areas under Roman rule. We have not, however, a single book or monograph treating of the social and economic life of the Roman Empire as a whole and tracing the main lines of its evolution. There are valuable contributions dealing with one or another partial problem or with some special period. Most of these contributions, however (for example, the excellent work of L. Friedlander), have been written from the antiquarian, not from the historical, point of view, and no one has endeavoured to connect the social and economic evolution of the Empire with its constitutional and administrative development or with the home and foreign policy of the Emperors. The present volume is the first attempt of the kind. I am very well aware that it is far from satisfactory. The task has been arduous and complicated. The material is scanty and scattered. No statistics are available. The interpretation of the few data which we have is open to dispute, and most of the conclusions drawn by modem scholars are hypothetical and often arbitrary. Yet, with all its drfficulty, the task is attractive in itself. I am convinced that, without a thorough investigation of the social and economic conditions, no attempt to write a general history of the Roman Empire can be successful.