An analysis of the suicide attacks against London transportation targets that killed 56 people and injured hundreds, by the author of Inside Terrorism. It was among the most important operations directed by core al Qaeda leaders in years following the events of September 11, 2001. Initially, the incident was dismissed by the authorities, pundits, and the media as the work of amateur terrorists—untrained, self-selected and self-radicalized, “bunches of guys” acting on their own with no links to any terrorist organization. Evidence presented here, however, reveals a clear link between the bombers and the highest levels of the al Qaeda senior command, then based in the lawless border area separating Afghanistan and Pakistan. Written by the author of Inside Terrorism, this chapter is part of the Columbia Studies series that examines major terrorist acts and campaigns undertaken in the decade following 9/11.