This subtitle might strike some readers as odd. Northern Ireland's conflicts have of course involved war of the bloodily physical kind, accompanied by clashes of symbols and slogans, loyalties and identities. Observers have often seen a war of religions, nationalities, or even tribes. But a "war of ideas" - what ideas?
Some retired gunmen have emerged as subtle political tacticians: most obviously Gerry Adams, but also figures like the Progressive Unionist Party's David Ervine. Many Irish republicans have placed great stress on a "correct" political analysis, especially when prison has given them enforced leisure for thinking. But no major works of political philosophy have emerged, even from the cell-blocks of the Maze.
The region's mainstream politicians have always included more clever lawyers - from Edward Carson to David Trimble - than subtle political theorists. Partly as a consequence, debate over Ulster's future, when not merely belligerent, has often been legalistic rather than principled. The conflict's literary legacy is strong on poetry and song, not on grand theoretical treatises.
Richard Bourke aims to show that, despite being such seemingly unpromising territory, Northern Ireland has indeed been the arena for a major conflict of political ideologies. This has, he argues, resonances that go far beyond the "narrow ground" of Ulster to pose important questions about our understanding of democracy and sovereignty.
Peace in Ireland falls, rather unevenly, into three parts. Its overt organisation is around two of these: "Republicanism and Imperialism", and "Unionism and Democracy". The third strand, intertwined throughout, is a detailed historical narrative of the "Troubles" and the search for a settlement. This story is vividly and even-handedly told, based on impressive research; but it is a familiar tale, and much seems only distantly relevant to Bourke's theoretical concerns.
With the latter, Peace in Ireland becomes challenging and original. Bourke's analysis of how republicans came to see their main enemy as British imperialism, and the consequences of that belief, is the weaker of his two motifs. The genealogies he constructs for the idea of imperialism are narrow, and he's too inclined to write as if republicans' view of it was simply a huge blunder, "imperialism" being a meaningless abstraction. Even if we agree that republican assumptions were mistaken, theirs was a more complex and interesting mistake than Bourke allows.
The arguments about unionism and democracy are stronger. The idea that Northern Ireland's history exposes the limitations of a conception of democracy which associates it simply with the will of the majority is hardly novel. The Stormont regime has often been viewed as a prime example of that point. Still, Bourke explores the implications with greater sophistication than almost anyone else.
Perhaps he's too impatient with some associated ideas: arguments over the making of political identities, group rights, and shared sovereignties. He's no doubt right that "joint sovereigty" is, strictly speaking, a logical impossibility. But that is a formalistic objection. It may be impossible in theory, but in practice something very like it now exists in the European Union, and may still prove to be Northern Ireland's best long-term hope.
The reviewer is author of 'Ireland and Empire' (Oxford University Press)