Can economics be applied to religion? Can a discipline dedicated to the study of markets have anything to say about matters of the soul? Adam Smith certainly thought it could, as the Wealth of Nations includes a discussion of how the vitality of religion withers when it is subsidized by the state. As do Rachel McCleary and Robert Barro in The Wealth of Religions: The Political Economy of Believing and Belonging. Their book is a primer on the growing field of the economics of religion—a fascinating area of research with lessons both for people interested in religion but not necessarily economics, and economists who may not be all that interested in religion.

Written for a general audience—no formal models or coefficient tables—the Wealth of Religions is filled with interesting and often counterintuitive findings about religion drawn from a wide swath of scholarship, including but not limited to the work of McCleary and Barro themselves. Here are a few examples: i) In a twist on Weber, the authors find that nations with widespread beliefs in heaven and hell experience greater economic growth. And, contra social capital explanations for the link between religiosity and growth, believing trumps belonging. Thus, nations with high rates of belief in an afterlife but low levels of religious participation still perform well economically. ii) By studying natural variation in the length of Ramadan based on when in the calendar it falls, Filipe Campante and David Yanagizawa-Drott find that this period of daytime fasting leads to lower economic growth but greater happiness (Quarterly Journal of Economics [May 2015]). iii) Where and when the Catholic Church has faced competition, either from Protestants or secularization, popes have accelerated the canonization of saints as a means to keep Catholics from leaving the faith. McCleary and Barro argue that “communal acts of devotion to saints reinvigorate the faithful through shared collective emotional and psychological experiences” (pp. 141–42).

I suspect that to some people who either study or practice religion (or both), this book will be unsettling because of a general aversion to economic principles applied to the divine. They may be concerned that economists are dilettantes, intent on blindly applying their methods and models without an appreciation for different religious beliefs and practices. Speaking as a noneconomist myself, I would encourage those skeptics to read this book. The Wealth of Religions has real depth in the substantive understanding of religion. For example, there is a lengthy discussion of the Geluk school of Buddhism, the branch associated with the Dalai Lama. There are similar explanations of Islamic history, the canonization process within Catholicism, and the fate of religion within formerly Communist nations.

The winning combination of data-driven economic analysis and careful discussion of theological and historical nuance arises from the complementary expertise of the authors. While Barro is a card-carrying economist, McCleary is a moral philosopher. Together, they provide a model for the application of economics to the study of a domain that, to many, might seem beyond the reach of standard economics. The lesson to be learned by economists, whether they are interested in religion or not, is the value that comes from blending the humanities with economics.

The book might also be unsettling both to those who criticize and lionize religion, as the authors follow the data wherever it may lead. Sometimes that means conclusions that are religion-friendly, such as the finding that a belief in an afterlife fosters greater economic growth. But other conclusions are not likely to be seen as pro-religion, such as the ways that strict religions spur their members to violence. It would not be accurate to call this book either pro- or antireligion. If the authors advocate for anything, it is the careful, empirical study of religion, which covers an enormous range of human experience. We should expect “religion”—broadly construed—to have a wide array of economic consequences, some positive, some negative, and some neutral. Indeed, this book may help defuse tensions over religion's role in society by imposing some empirical discipline on what are often wild and unsubstantiated claims by both religion's opponents and advocates.

For all of its virtues, though, consider this book more of a good start than the final word on the economics of religion. For one, the topics covered are idiosyncratic, driven mainly by the various questions taken up within the small literature on religious economics. These topics are influenced by the incentives of the discipline, such as the availability of data and the need for a plausible empirical approach to determine causation (what economists call an identification strategy). Many questions remain: Can economics shed light on the reaction of religious institutions to sexual abuse within their ranks? Why do religions become involved in partisan politics? Or governments’ deployment of religion to bolster nationalism? To their credit, McCleary and Barro often note areas for further exploration, and not just in the formulaic way that many academic works conclude by calling for future research. Rather, they sprinkle these observations throughout the text, at times even providing specific examples of the data that could be used to answer the unanswered questions they mention. To any scholar seeking ideas for future research, this is the book for you.

As the field of religion economics grows, I hope that future researchers will follow the lead of McCleary and Barro and look beyond economics as narrowly defined to inform their work. In doing so, however, I recommend that subsequent work look not only to the humanities but also to disciplines closer to home, specifically in the other social sciences. There are references here and there to research in fields such as sociology, psychology, political science, and anthropology, but no mention of many other large and mature bodies of work on religion in all of these areas. Incorporating this scholarship would enrich the economic analysis, and only sharpen how an economic perspective makes a novel contribution to religious research.

Can economics be applied to religion? The Wealth of Religions demonstrates that economics does indeed have a lot to add to the study of religion. And the study of religion also has a lot to add to economics.