Abdallah Azzam, the Palestinian cleric who led the mobilization of Arab fighters to Afghanistan in the 1980s, played a crucial role in the internationalization of the jihadi movement. Killed in mysterious circumstances in 1989 in Peshawar, Pakistan, he remains one of the most influential jihadi ideologues of all time. Here, in the first in-depth biography of Azzam, Thomas Hegghammer explains how Azzam came to play this role and why jihadism went global...