The nineteenth-century historian Sir John Seeley famously remarked that the British "conquered and peopled half the world in a fit of absence of mind." Seeley was right that the United Kingdom's empire was neither planned nor coherent. Yet nonetheless it was, as the title of this book suggests, a "project," resulting from the deliberate, largely self-interested choices of British decision-makers. It also required, to a surprising extent, the cooperation of elites and masses in the territories that composed it -- without which, British power and wealth alone would surely have been insufficient. Oxford University's Darwin offers a brilliant modern synthesis of the project's history. The guiding theme is the rise and fall of the United Kingdom's power and wealth -- resulting from geopolitical forces over which the British had little control. He is particularly good on the empire's ineluctable but slow decline, arguing that only in the midst of World War II did it become clear that the nineteenth-century conception of empire was finished. Yet in telling the story of a great power's inevitable trajectory, Darwin does not neglect history's humanistic, less predictable side: the United Kingdom's clever diplomacy, the remarkable ethnic solidarity felt by the descendants of settlers, the role of imperial romanticism among both the conquerors and the conquered, and the extraordinary individual personalities behind the scenes. This long yet readable book is now the best general history of the British Empire.