This study, first published in 1986, examines the evolution and application of the policies of wartime governments designed to deal with the danger to national security thought to be posed by enemy alien residents, and considers the social and political forces which helped shape these policies. The scope of the powers assumed by the authorities to regulate the entry, departure, movement, employment, business activities and many other facets of the lives of aliens were unprecedented in war or peace. This book will be of interest to students of history.