This is an astonishingly good book. It is an important one too. Its immediate provenance is the author's Carlyle Lectures in the History of Political Thought at the University of Oxford in 2006. These were built upon Kidd's deeply learned and formidable contributions to the history of ideas in Scotland, beginning with his first major book, the seminal Subverting Scotland's Past, published in 1993. The book is an expanded version of the lectures. Perhaps because of this, Union and Unionisms has a mildly polemical tone and contains too a few provocative barbs. Rarely, however, does Kidd claim more than the evidence can bear. His challenge is to those historians and literary scholars who from the time of Hugh MacDiarmid onward (i.e., from ca. 1930) have privileged nationalism in Scotland over Scottish unionism. Unionism, Kidd proposes, has been portrayed as a form of English imperialism, “an unnatural perversion” (3), antithetical to Scottish interests, and scarcely worth studying. Yet, if in its relatively recent Thatcherite formulation unionism became stridently interventionist in terms of the role of the British state, and as vehemently opposed to devolution, it was not always thus. Indeed, what this book succeeds in demonstrating is that unionism in Scotland has a centuries-old pedigree dating back to the sixteenth century and has taken many forms. The proposition, that for long periods unionism and unionists have had much in common with certain variants of Scottish nationalism, may come as a surprise to many readers—although as Kidd points out in a footnote (299), even the present Scottish National Party–led government aspires to unravel the Union of 1707, not the 1603 Union of the Crowns. But there are several other surprises in this lively, lucid, penetrating, and thought-provoking book.

The book comprises seven substantive chapters, each dealing with a different aspect of unionism: unionisms (the use of the plural is important) prior to 1707, constitutional unionisms, unionisms and the law, and the ecclesiology of union, to name but four. Kidd coins a new term, “banal unionism,” which alludes to the marginal role played by the Union of 1707 in Scottish political discourse from 1746 until the 1970s; in other words, union was the natural, largely unnoticed, order of things. But this is far from saying that unionists were silent, or closet English imperialists, but rather that in a range of creative and ingenious formulations, unionists in the intervening centuries wrote and spoke in defense of Scottish interests, with their proposals for different forms of association with England invariably being “tinged with nationalist considerations” (300). It will come as less of a surprise than it might have prior to the recent publication of some studies of the Union of 1707 that the unionism that in part informed the Anglo-Scottish union owed much to Scottish enthusiasm for such a step, based upon the fact that the peoples of the two nations shared a single land mass as well as the Protestant religion and were damaged by conflict between them. Such notions were central to Whig Revolution ideology in Scotland. What does seem remarkable, however, is that despite the separate act in 1706 designed to secure the Church of Scotland within the union, the status of the kirk in the uncodified British constitution still remains uncertain in 2009. If Kidd goes a mite too far in suggesting that the Protestant religion was the grit in the Union rather than its glue—surely it was both—what is utterly convincing is his argument that until the Church of Scotland Act (1921), it was religion that divided Scots and English, not union itself. Intriguingly, however, Kidd proposes that the Scottish legal system played a much less substantial part in defending Scottish national identity post-1707 than has often been assumed. On the contrary, Scottish legal culture was “predominantly unionist” (175), not only during the eighteenth century when Kidd detects a strong anglicizing tendency among Scottish Enlightenment jurists but also toward the close of the twentieth century, when a form of legal nationalism emerged, the advocates of which were more often than not content to work alongside (but not subordinate to) English and European systems.

On other issues too, Kidd tackles cherished positions, as for instance the assumption that political nationalism is progressive and preordained and that today's Scottish National Party is the direct successor in a line of nationalist bodies and groupings dating back to the National Association for the Vindication of Scottish Rights (1853–56; NAVSR). Thus, the first Scottish home rulers were unionists at heart, while at the point of its formation the Scottish National Party envisaged a future in which Scotland would have a separate parliament but would sit alongside England as a “mother nation” of the empire. None of this is to diminish the enormously powerful sense of nationality felt by Scots in the nineteenth century, evidenced less by the rather small crowds that attended the NAVSR meetings reported by Kidd but rather—for example—by the gathering of 50,000 or more people at the Burns Festival at Ayr in 1844. The proceedings, wrote one seasoned journalist from London, were the most fervent he had ever witnessed and represented the “heart-beatings” of the Scottish people. Were those present unionists too? It would seem so.

Kidd concludes with the hope that Scottish historians reading his book will feel unsettled about their use of the analytical categories nationalist and unionist. They will—or should. But there is much to be learned by anyone interested in the formation and development of Britain over the past four centuries. Rightly, Kidd credits Linda Colley's Britons: Forging the Nation, 1707–1837 (New Haven, CT, 1992) with being one of the most influential books of our times. Union and Unionisms has the potential to acquire similar status.