With one foot in South Africa (Cape Town) and another in Australia (Sydney), Kirsten McKenzie has the makings of a colossus when it comes to networked British imperial history. And, of course, there was the metropole, where statesmen struggled to contain the centripetal diversity of the various British possessions. Not that the various colonies were looking for independence at this time, but so many people in them were trying different ways of being British. Britishness, as McKenzie shows in Imperial Underworld: An Escaped Convict and the Transformation of the British Colonial Order, was proving in these first decades of the nineteenth century an extraordinarily protean and fruitful thing.

McKenzie has already written two books that trace connections of this sort. More profoundly, she has a continuing interest in the way the empire reshaped the identity of individuals. This was partly an issue of geography and communications. It was relatively easy to transform one's identity in moving from one British possession to another, because news as to who you really were might follow you fairly slowly and obscurely. The information economy of empire, including its bureaucracy, was itself being transformed, and those who wanted a new disguise had to hurry ahead of such progress, using some skill and address.

But it was also an issue of increasing social mobility. The empire was growing in size not just because of military success but also because of industrial and cultural productivity, and a mass of new money made it possible for individuals to move upwards more easily, which in turn created some confusion of rank, as traditionally formulated. And then there were the changes in the law and in ideas about the law, which gave new precision to individual rights and raised large questions about the definition of the British subject. Aggrieved individuals and suspected transgressors were all more likely to be more carefully heard than hitherto. The precise status of emancipated (or pseudo-emancipated) slaves, transported convicts, and indigenous men and women were particularly live issues.

McKenzie makes this all clear. “I take the messiness of real social and political relations as my guide to the history of constitutional change,” she says (194)—not the other way around. This approach calls for painstaking work. It involves detailed exposition, and from a presentation point of view there are large challenges of balance and continuity. In a sense, this book might have been much longer—as if we might need from McKenzie a sequel to Linda Colley's Britons. McKenzie's delight in tracking maverick lives, her fun with the interplay of structure and eccentricity—in short, her skill as a conjurer—is lovely to watch, and the reader cannot help feeling that there is a lot more yet to learn from it. We might have more, for instance, on the redefinition of property as an aspect of human identity, not just property in human beings but property of human beings. And while government espionage, personified by Oliver the Spy, is nicely dealt with, there is clearly more to say there, too. Potentially, the subject of this book is massive.

Mackenzie does not explore this issue, but the growth of the newspaper press put pretenders of all sorts on a much larger stage than hitherto, dressing them in colors to attract attention. Newspapermen's refinement of spin and a new degree of sensationalism drove this process. The suddenly increasing power of mass public opinion, as with today, was morally ambivalent. It effected, say, the abolition of the slave trade and other humanitarian reform, but it also created a much more slippery kind of truth.

This is the world that Kirsten McKenzie has made her own, and the best thing about it is that in her hands her showmen remain real and sometimes tragic human beings. In her previous two books, Scandal in the Colonies: Sydney and Cape Town, 1820–1850 (2004) and A Swindler's Progress: Nobles and Convicts in the Age of Liberty (2009), she told various stories of shape-shifting. Prominent among her characters was the convict John Dow, who toured New South Wales in the 1830s pretending to be the son and heir of the Earl of Harewood. But then the Harewoods themselves had lately been colonials, and had changed their character very quickly from slave-owners to noblemen.

The individuals concerned had a more or less distinct understanding of themselves situated within the network of empire. Invited to share it, readers are given a means of escape from the narrower mindset that has been integral to the writing of their own national histories. Britain, rather than being the great antagonist, becomes instead a single point, though the most important, in an intricate pattern. In this book, the work of John Thomas Bigge, who was a judge in one colony and a commissioner of inquiry in two, looks entirely different from hitherto, and McKenzie makes some striking comments about the way he has been variously represented in the South African and Australian stories. He too, though posthumously and unwittingly, has changed his character according to his circumstances. The third earl Bathurst, secretary of state for the colonies, is a fairly well-known figure. But he takes on new subtlety and depth when seen dealing with the unruly complexities of law, personality, and politics from colony to colony, as happens here. For those of us who have spent decades laboring within a single national tradition and within the old imperial framework, McKenzie's way of setting national traditions side by side is refreshing indeed.

This book, and McKenzie's work as a whole, opens so many new doors that it is tantalizing to imagine how it might all be worked through in a more comprehensive volume. The single best thing about her approach is the way in which she poses and partly answers such large new questions and at the same time recreates individual lives in such a vivid and touching way.