During late antiquity the Roman empire faced serious threats from the peoples to the east and to the north. This book is concerned with the role played by information and intelligence in the empire's relations with these peoples, how well-informed about them the empire was, and how such information was acquired. It deals with an important facet of late Roman history which has not previously received systematic treatment, and does so in a wide-ranging manner which relates the military/diplomatic history to its broader social/cultural and economic context.