When they showed up in Syria with a long beard and toting an AK-47 or staged a murderous attack on their fellow Europeans, their families always professed surprise and incomprehension at the transformation. Roy has described this not as the radicalization of Islam, but the Islamicization of radicalism—that is, a process that draws from the same alienation that drove earlier generations of extremists, whether nationalists such as Paul de Lagarde or Communists such as Leon Trotsky.8
