Osama bin Laden became the face of militant Islam following the September 11, 2001 attacks in New York, and it was these attacks that propelled his organisation to the world's attention. 

So without bin Laden, what happens to al-Qaeda?

His most obvious successor is Ayman al-Zawahiri. Born in Cairo he was a key figure in the Egyptian Islamist movement. He fought against the Soviets in Afghanistan and was bin Laden's closest adviser.  

Another potential replacement is Anwar al-Awlaki. Born in New Mexico, he has now become the spokesman for al-Qaeda in the Arabian Peninsula. Seen more as a cleric than a fighter, Awlaki is believed to have played a key role in a number of terrorist plots in the US.

There is also Abu Yahya al-Libi. A leading al-Qaeda ideologue, he was a commander in Afghanistan. Al-Libi has been active in urging resistance and recruits from Europe and North America. 

Who, among those, will be Bin Laden's successor? With the death of its iconic leader, how will the organisation operate in the future? And how will Western countries adapt to the changing face of the group?

Inside Story, with presenter Darren Jordon, discusses with Imtiaz Gul, a political analyst and author of several books on al-Qaeda including The most Dangerous Place: Pakistan's Lawless Frontier; Paul Rogers, a professor of peace studies at the University of Bradford; and Mahan Abedin, the director of research at the center for the study of terrorism, who the co-edited Unmasking Terror: A Global Review of Terrorist Activities.

This episode of Inside Story aired from Wednesday, May 4, 2011.