Islam, Authoritarianism, and Underdevelopment is an impressive book. It asks big and important questions about the origins and evolution of democracy and economic development. It is theoretically ambitious in its efforts to explain long-term developments in economics, politics, and political violence. It is empirically ambitious in its treatment of political and economic development over more than one thousand years, drawing on a painstaking reading of Islamic philosophy and synthesizing development indicators from forty-nine Muslim-majority countries.

Ahmet T. Kuru seeks to account for the divergence of the Muslim world and Western Europe over the longue durée. Why, given Muslim scientific, military, and political advancement from the seventh to the eleventh century, did Europe pull ahead of the Muslim Middle East during the fifteenth to the seventeenth century, so that by the eighteenth, nineteenth, and twentieth century, European powers were able to subjugate and colonize Muslim-majority countries, and today surpass them in literacy rates, years of education, life expectancy, gross national income, and democratic development? Kuru argues that an eleventh-century alliance between Muslim clerics and political rulers stifled the engines of development, namely, independent intellectuals and a powerful bourgeoisie (merchant class). That stifling continues today, and Kuru argues that it explains the democratic deficit and economic backwardness of Muslim-majority countries compared with both Europe and the globe.

Kuru's main interlocutors are giants of the social sciences: Timur Kuran, Bernard Lewis, and Avner Greif. These are all men who have sought to explain civilizational advance or decline using similarly long-term structural explanations: For Kuran, it is the inflexibility of Islamic law that hobbles the equitable distribution of inheritance and the creation of corporations that are necessary for capitalist democracy.Footnote ¹ For Lewis, Islam itself is the problem.Footnote ² For Greif, it is the individualist culture of Europe.Footnote ³ Kuru says that these men's explanations are wrong or, in the case of Kuran, incomplete. Instead, Kuru demonstrates that the reason for the divergence is political and ideational; an eleventh-century alliance between rulers and clerics hobbled the advancement of the ideas—reason, individualism, pluralism—and the class relations that Kuru argues are the engines of development.

Kuru forces scholars to take ideas seriously as structural variables in longue durée explanations and pushes back against materialist, institutional, or cultural accounts. Part of the reason why Kuru's account is compelling is that it is familiar. Kuru's argument is the classical liberal view applied to a new domain. Here is Adam Smith in The Wealth of Nations:

Like Kuru, Smith is not giving a cultural explanation about the detrimental effects of Christianity, or a material explanation about medieval European backwardness, but rather an explanation of the negative effects of an alliance of church and state on the development of political liberty, reason, and markets. Cleric-state or church-state alliances and the concurrent policing of heterodoxy has detrimental effects for philosophers regardless of their material or civilizational background. Once ideas are allowed to circulate, Smith and Kuru argue, then reason will triumph over superstition (doctrine) and clerics will be forced by the civil magistrate, the powers of commerce, and the public to dispatch churches to the spiritual realm. Thus does liberty and prosperity originate.

A significant contribution of the book is that in order to unearth the origins and endurance of the cleric-state alliance, Kuru invites readers to eavesdrop on fascinating debates between Muslim philosophers. They include Mawardi, the eleventh-century Shafi‘i scholar who was influential for the legitimation of the idea of a unitary caliphate rather than differentiation in state and religion; Al-Ghazali, the eleventh-century Persian philosopher whose ideas about orthodoxy proved influential for the persecution of heresy and the necessity of an cleric-state alliance; Ibn Khaldun, the fourteenth-century Tunisian scholar whose structural and sociocultural and political analysis anticipated nineteenth-century European social science theory but was subsequently neglected; the seventeenth-century Ottoman scholar Katip Çelabi's work on governance problems in the Ottoman state, and others. In making a structural argument about the power of ideas, Kuru celebrates the work of Muslim philosophers while lamenting the limits of their impact.

Another highlight of the book is Kuru's genealogy of an ideational poison pill; Ghazali is the book's antihero who defends the idea of a religion-state alliance using the pronouncement that “religion and the sultan (or the state) are twins; religion is the foundation while the state is the guard” (p. 8). Kuru traces that pronouncement to the pre-Islamic Persian Sasanian Empire. Other Muslim scholars—Nizam al-Mulk in the eleventh century, Fakh al-Din al-Razi in the twelfth century, Umar Suhrawardi and Nasir al-Din al-Tusi in the thirteenth century—all use it to promote the cleric-state alliance while repressing heretical and heterodox ideas. Unearthing the structural effect of ideas is a very difficult feat, and scholars are lucky to have Kuru demonstrate the power of repressive ideas over time and space.

As with any monumental text, Kuru's tome includes minor shortcomings that are particularly germane to scholars of Asia. Kuru's argument about democratic and economic development hinges on not just the marginalization of philosophers but also the lack of an independent bourgeoisie (p. 64). Yet while the text devotes dozens of pages to the repression of intellectuals and the crafting of the cleric-state alliance, it is empirically thin on the marginalization of the bourgeoisie. That gap raises concerns about how far the argument travels; the spread of Islam in the Indian Ocean region, home to the majority of the world's Muslims, was propelled by influential merchants from the eighth to the seventeenth century and then again in the nineteenth and twentieth centuries when middle-class reformers spread ideas from Muhammad Abduh and Rashid Rida to the Islamic organizations that continue to be the backbone of democracy in Indonesia.Footnote ⁵

A second concern is the scope of the argument. A similar book by Kenneth Pomeranz, The Great Divergence, stops the analysis prior to the twentieth century, since Japan, South Korea, Thailand, Malaysia, Singapore, and Hong Kong approached or caught up to Western European countries in that period.Footnote ⁶ There are now many middle- and high-income countries with institutions similar to Western Europe owing to twentieth-century convergence. Why did those countries catch up, but, according to Kuru's account, the Muslim-majority countries did not? Most likely the levels of economic and political development are attributable to the twentieth-century adoption and adaption of European institutions, rather than to events in the eleventh century.

Minor concerns aside, Kuru's book is a pleasure to read and merits wide reading and engagement by historically inclined scholars of religion, politics, and economic development.