Karl Hack, Professor of Asian and Imperial History, has published this article that includes a sweeping view of British imperial history as seen through the eyes of John Darwin’s works, and a survey of the state of the ‘decolonisation’ field. The article locates John Darwin’s work on decolonisation within an Oxbridge tradition which portrays a British world system, of which formal empire was but one part, emerging to increasing global dominance from the early nineteenth century. In this mental universe, decolonisation was the mirror image of that expanding global power. According to this point of view, it was not the sloughing oﬀ of individual territories, but rather the shrinking away of the system and of the international norms that supported it, until only its ghost remained by the end of the 1960s. The article then asks, echoing the title of Darwin’s Unﬁnished Empire, whether the decolonisation project is all but complete, or still ongoing. In addition, what is the responsibility of the imperial historian to engage with, inform, or indeed refrain from, contemporary debates that relate to some of these issues? The answer is twofold. On the one hand, the toolkit that the Oxbridge tradition and Darwin provide remains relevant, and also useful in thinking about contemporary issues such as China’s move towards being a global power, the United States’ declining hegemony, and some states and groups desires to rearticulate their relationship with the global. On the other hand, the decline of world systems of power needs to be recognised as just one of several types of, and approaches to, analysing ‘decolonisation’. One which cannot be allowed to ignore or marginalise the study of others, such as experience, ﬁrst nations issues, the shaping of the postcolonial state, and empire legacies. The article concludes by placing the Oxbridge tradition into a broader typology of types and methodologies of decolonisation, and by asking what a new historiography of decolonisation might look like. It suggests that it would address the Oxbridge concern with the lifecycles of systems of power and their relationship to global changes, but also place them alongside, and in dialogue with, a much broader set of perspectives and analytical approaches.