Barbara Levick & Barbara (University of Oxford, UK) Levick 
The Government of the Roman Empire [PDF ebook] 
A Sourcebook

This book reveals how an empire that stretched from Glasgow to Aswan in Egypt could be ruled from a single city and still survive more than a thousand years. The Government of the Roman Empire is the only sourcebook to concentrate on the administration of the empire, using the evidence of contemporary writers and historians.
Specifically designed for students, with extensive cross-referencing, bibliographies and introductions and explanations for each item, this new edition brings the book right up-to-date, and makes it the ideal resource for students of the subject.