In this book James Turner Johnson explores the cultural traditions of the Christian West and Islam, in an effort to encourage a constructive dialogue on the nature of war for religion. No other issue highlights the difference between these two cultures more clearly or with more relevance for their interrelations throughout history and in the contemporary world.

In the West, war for religion is most often dismissed as a relic of the past, belonging to a time less rational and less civilized than our own. From this perspective, Muslims who advocate holy war are seen as religious fanatics who are supporting criminal and terrorist activity. By contrast, war for religion has an honored place in the Islamic world, associated with a perennial religious requirement: striving in the path of faith by heart, tongue, and hands. This striving is designated by the now familiar term jihad. In fact, striving by the sword is the "lesser" jihad, and many Muslims themselves are troubled by reductionistic appeals to jihad to justify terrorism, revolution, and anti-western activity. According to Johnson, for there to be any dialogue between Islam and the West we must understand that in the West religion and politics are placed in separate spheres, while normative Islam regards religion as properly integral to the political order. From this perspective religious concerns should have a place in statecraft, including the use of military force.

Three questions form the heart of Johnson's inquiry: Is there a legitimate justification for war for religion? What authority is required? What is the proper conduct in such wars? In each case, he asks the question by comparing religious wars with other kinds of wars. The picture that emerges is of war for religion not as an expression of fanatical excess but as a controlled, purposeful activity. With an eye to the present day, Johnson examines cases in history where distinctive models of war for religion were implemented by rulers. This in turn sets the stage for critical judgment on contemporary appeals to the idea of jihad in relation to political aims.

Well known for his work on peace and just war, Johnson draws upon a wide base of historical and comparative scholarship. While the book is anchored primarily on the past, on the roots and historical development of the two traditions, his aim throughout is to shed light on contemporary attitudes, ideals, and behaviors, especially as they bear on real problems that affect relations between Western and Islamic cultures in the world today.