Assuming that most Americans know little about Islam, Marshall, Green, and Gilbert collaborated to produce a succinct book explaining the difference between the religion and its radical, minority offshoots. The reader is invited to look critically at the history of Islam, its basic tenets, its relationship with the West, and its modern radical roots … all in a couple of hours.

Indeed, the book’s brevity is both its best attribute and its greatest limitation. In less than thirty pages, Islam at the Crossroads ambitiously attempts to tackle the history of Islam from the rise of the Prophet Muhammad to the fall of the Ottomans after World War I. While helpful to get a sense of the whole, the simplification tends to gloss over some of the debates raging between experts in the field, particularly when dealing with the contentious history of early Islam.

At a time of reflective ecumenicism, the authors courageously note, quoting the German scholar Tilman Nagel, that concentrating on similarities between world religions to reduce tensions amounts to “ignorance.” For those who would reduce the differences between Christianity and Islam, our authors offer a table to show how major and irreconcilable these differences are.

The authors provide useful capsule accounts of Wahhabism, the Muslim Brethren, and the teachings of Sayyid Qutb, Ali Shari`ati, and Ayatollah Khomeini. The goal of these movements and thinkers then is the same as the goal of Islamists today: to strengthen the power of Islam and weaken that of others. The conflict between the West and Islamism, we are reminded, is not about poverty, globalization, or ignorance. It is about power.

Islam is indeed at a crossroads, choosing between moderate and radical interpretations. And while Muslims work through their current crisis, the authors correctly encourage the West to “recognize and support the voices of moderate Islam.”