Since the end of the Cold War and 9/11, religion has made a comeback in the study of world politics. Religion has apparently become more contentious and this has stimulated a growing body of literature. While most work has focused on violent conflict, Zeev Maoz & Errol A Henderson analyse a wider scope. This unique, comprehensive study looks at the effects of religion on cooperation and on 'human security', which includes several aspects of development such as socioeconomic well-being, gender equality and civil liberties. The multi-faceted global regression analyses include the finding that no specific faith appears more prone to conflict or cooperation than others. However, international cooperation seems more likely when states share faiths. Interestingly, secularism significantly increases human security. It is laudable that the authors engage in a broad, global and quantitative approach that seems required for reaching general conclusions on the relationship. The book also convinces by being very transparent, especially through an extensive appendix. Some scholars might of course have preferred to use other data sets than the one created by the authors and they might have wished to focus less on demographic aspects and more, for instance, on religious ideology and governance. In methodological terms, some endogeneity issues persist. For instance, is secularism an independent cause of higher human security or just part of a larger trend of modernization? Such scholarly criticism should not be overestimated. The topic is timely and pertinent, and the book is comprehensive and offers much thought-provoking theorizing and many stimulating results – exactly what great scholarship should do.