At the beginning of the fifth century, St Augustine, bishop of Hippo, contemplated from his North African home the still-vast domains of the Roman empire. He debated the question of whether it was fitting for good men to rejoice at the expansion of empires over less civilised peoples. He concluded that extending rulership over subjugated nations might seem to bad men felicity, but good men could accept it as a necessity. Many generations since have asked the same question as Augustine, when they encountered empires of all kinds, from theocracies to thalassocracies. Some have been called beneficent, designated with the honorific ‘Pax’. Some have been called evil. All of them have excited controversy and continue to do so. The British empire is no exception. None, however, rivalled it for complexity and geographical spread. Those who ran it firmly believed in its fundamental Augustinian necessity. Their sense of duty perhaps blinded them to an inherent infelicity.

To understand this complicated and ambivalent British enterprise is a challenge, but a rewarding one. Writing about British overseas experience has been opened up fruitfully in several directions in the past fifty years. Fresh perspectives have come from the concept of ‘informal empire’, and from different disciplines, such as global and comparative history, from anthropology and ‘history-from-below’, and from various manifestations of cultural history, such as sport, masculinity, and women's history.