Despite the frequent appearances of Osama Bin Laden and Ayman al-Zawahiri on television screens worldwide, Al Qaeda remains an elusive entity. As the world has grown increasingly familiar with the spectacle of Islamist terrorism, Al Qaeda's essential worldview has remained bewilderingly opaque. To reveal its inner workings, Gilles Kepel and his collaborators, all scholars of Arabic and Islam, have collected and brilliantly annotated key texts of the...