Nationalist historians have argued, variously, that Australia was betrayed by Britain in 1941-42 with the fall of Singapore, and plunged into crisis, or conversely, that the nation was 'armed and ready' for the much feared Japanese invasion. Arguing that neither proposition is true, this thesis establishes that Australia was not armed and ready even for a much feared large-scale Japanese invasion. Nor was the nation ready for the small-scale Japanese attacks which were more probable and which, under Imperial defence, were a local defence responsibility. This thesis explains why Australia was unprepared. It does this by exploring Australian understandings of Imperial defence, assessing Australian responses to international crises 1919-1939, evaluating criticisms of those responses, and analysing the nature of domestic politics. It concludes with a socioeconomic analysis of Australia's key elites - political, military, and industrial.(Open document for complete abstract)