A quarter-century after the attacks that killed nearly 3,000 people, the name Osama bin Laden remains burned into American memory. Far fewer recognize the man who helped shape him.

Abdullah Azzam, a Palestinian Islamist from Jenin, served as one of bin Laden’s most important mentors. In the 1980s the two men co-founded Maktab al-Khidamat (the Services Bureau), the network that recruited, financed, and supported Arab fighters joining the Afghan jihad against the Soviet Union. That organization supplied both the personnel pipelines and the organizational habits that later fed into al-Qaeda.

Azzam was assassinated in 1989. His ideas and the networks he helped build outlived him. They formed part of the ideological and logistical foundation for the movement that produced the September 11 attacks.

Historians and counterterrorism analysts have long noted that understanding the origins of al-Qaeda requires looking beyond the most famous names. Azzam’s role as theorist, recruiter, and organizer remains one of the least widely known chapters in that story for the general public.

Twenty-five years later, the people who constructed the movement that carried out 9/11 still receive far less attention than the catastrophe they helped make possible.

This report draws on established historical and counterterrorism scholarship regarding the founding of Maktab al-Khidamat and its role in the formation of al-Qaeda.