In his preface, Richard Overy explains that he has based this monumental reassessment of the Second World War on four assumptions. The first is that the conventional chronology of 1939–45 is no longer useful. The second is that the war must be understood as a global event since the Asian and Pacific theatres were as important as the European one, and possibly more so in their consequences. The third is that it encompassed a number of different kinds of war, with civil conflicts running alongside conventional military operations. The fourth is that this was essentially an imperial war that brought to an end the era of traditional colonial rule and left in its wake a world of nation-states rather than empires.

Citing the huge amount written over the past decades on the war itself, he devotes fewer than 350 out of nearly 900 pages to a masterly overview, which makes a well-known story exciting to read. He supports this with thematic sections on the process of mobilising people and