Our joint work, like so much else in life, had its origin in an accident of fate. It would never have seen the light of day, at least in its published forms, had it not been for the chance that the authors both came to the University of Birmingham in the mid-1960s, from different backgrounds and with different interests, and then found that, by the mid-1970s, their research interests had converged to the point where co-operative work began to appear both logical and feasible. At that moment, like countless other scholars in all branches of research, we did not have a clear idea of what we were embarking on or, of course, how long it would take. But we made a conscious decision, at a time when we had built up a considerable amount of intellectual capital, to attack one of the big problems of modern history, namely the causes of imperial expansion, and to take a chance on the outcome.