Studies of the onset of World War II are, of course, numerous, covering both its origins in Europe in 1939 and the origins of the war in the Pacific at the end of 1941, and this book does not aim to duplicate them. Its aim is to relate the events they describe to those in Southeast Asia, which, interesting in themselves, also offer a clue to understanding the transition from European war to world war. The principal focus is on the role of the British and their relationships with the territories they did not formally control.

Britain's main aim in Southeast Asia in this phase was to continue to preserve the status quo, so far as it was possible, without getting involved in an additional war. That involved attempts not only to prevent the military expansion of the Japanese but also to restrict their penetration into the area, in particular by encouraging elements of resistance to the pressure they felt increasingly able to exert because of the course of the European war. If the invasion could be averted then it might be possible to prevent a Japanese takeover by other means. If the invasion could not be averted, it might at least be made more difficult.

What the British could do in either respect was limited. Unable to maintain effective land, sea or air forces in the East, they sought to use the other strengths, commercial and financial, on which their position in the world had long relied.