Karsh, head of the Mediterranean Studies Programme at King's College in London, situates historic Islamic expansionism—as well as the contemporary violent acts of bin Laden and other jihadi terrorists—within the context of the imperative Muhammad gave to his followers: "I was ordered to fight all men until they say, ‘There is no god but Allah.'" The contemporary impulse of violent jihadi groups to establish Islamic states from Indonesia to Nigeria, argues Karsh, is not a reaction to Western colonialism or U.S. foreign policy; nor, however, is it solely or simply a manifestation of some inevitable Islamic/Christian clash of civilizations, nor of the frustration that Muslims feel at no longer commanding the global power once wielded by the great Islamic empires. Rather, says Karsh, "the Middle East's experience is the culmination of long-existing indigenous trends, passions, and patterns of behavior, first and foremost the region's millenarian imperial tradition."

Many of these, Karsh points out, predate Islam; however, Muhammad's command to convert or subjugate non-Muslims "at once tapped into the Middle East's millenarian legacy and ensured its perpetuation for many centuries to come." Modern-day Arab imperialism (of the Baath movement and others) was perhaps inevitably only a detour from the religious imperialism that began its resurgence with the Khomeini revolution in Iran and would, eventually, absorb Arab nationalism and redirect its energies for its own purposes.

The Islamists, notes Karsh, "modeled themselves on Islam's early conquerors, and aspired to nothing less than the substitution of Allah's universal empire for the existing international system." The evidence he presents in this book of the continuity of the motives and goals of Islamic imperialists from Muhammad's day to our own should be sufficient to put paid to the simplistic and misleading notion that Islam is a religion of peace that has been hijacked by a tiny minority of violent extremists—and should lead, in the hands of policymakers of sufficient imagination and courage, to more realistic ways of dealing with this newly resurgent challenge.