How did Great Britain and France, the largest imperial powers of the early twentieth century, cope with mounting anticolonial nationalism in the Arab world? What linked domestic opponents and foreign challengers in the Middle East and North Africa - Syria, Palestine, Transjordan, Iraq, Tunisia, Algeria, Morocco, and Egypt - as inhabitants attempted to overthrow the European colonial order? What strategies did the British and French adopt in the face of these threats? "Empires of Intelligence", the first study of colonial intelligence services to use recently declassified reports, argues that colonial control in the British and French empires depended on an elaborate security apparatus. Martin Thomas shows for the first time the crucial role of intelligence gathering in maintaining imperial control in the years before decolonization.