Osama bin Laden: A member of the wealthy Saudi Bin Laden family, he founded al-Qaeda in the 1980s to assist Arab fighters into Afghanistan to fight the Soviet occupiers. When that battle was won, he redirected his energies against US ‘crusaders’, focusing on a campaign to remove US forces from Saudi Arabia. The alleged mastermind behind the 9/11 terror attacks is thought to be in hiding somewhere in Waziristan on the border between Afghanistan and Pakistan, but appears to be in poor health and is rarely heard of.
Ayman al-Zawahiri: The al-Qaeda second-in-command, is a qualified surgeon who speaks English, French and Arabic. An Egyptian national, he was formerly the leader of the Egyptian Islamic Jihad, which he merged into al-Qaeda in 1998. He regularly makes video appearances on Islamist websites, exhorting his followers to carry out attacks on targets in the west. He is also thought to be operating from somewhere in Waziristan.
Abu Ayyub al-Masri: The new leader of al-Qaeda in Iraq is an Egyptian believed to have much closer ties to Afghan- and Pakistan-based al-Qaeda leaders like bin Laden and Zawahiri than his predecessor Abu Musab al-Zarqawi did. He appears to be trying to alter al-Qaeda’s reputation as a foreign-dominated band of terrorists.
Abu Musab Abdul Wadud: The current head of al-Qaeda in the Islamic Maghreb (AQIM), and a former science student who dropped out of university after two years and is thought to be a bomb maker.
Saif Al-Adel: Egyptian operative in Africa who allegedly helped plan the 1998 bombings of US embassies in Kenya and Tanzania. An instructor and military commander for al-Qaeda. He is thought to be in Iran.
Fazul Abdullah Mohammed: The supposed leader of al-Qaeda’s East African presence. An unconfirmed newspaper report in February claimed that he was living on the island of Madagascar.
Fahid Mohammed Ally Msalam: The Kenyan national is thought to have supervised the Dar Es Salaam bombing. His current whereabouts are unknown.
Abdullah Ahmed Abdullah: an Egyptian national wanted in connection with the 1998 US Embassy bombings, is believed to have to have helped Saif Al-Adel set up al-Qaeda training camps in Somalia.
Khaled Sheikh Mohamed: A former member of al-Qaeda in Kuwait, he is alleged to be the principal architect of the 9/11 attacks. He is also thought to have had, or confessed to, a role in many of the most significant terrorist plots over the last twenty years. Captured in Pakistan in 2003, he was moved last year from a secret prison to Guantanamo Bay.
Abu Musab al Suri: Syrian mechanical engineer who fought alongside Osama bin Laden in Afghanistan and has long been considered a leading ideologue for al-Qaeda. Thought to have been captured in 2005.
Anas Al-Liby: Once granted political asylum in the UK, he is believed to have fled to Afghanistan to escape prosecution for his involvement in the 1998 US Embassy bombings. On Amnesty International’s list of possible US-held secret prisoners.
Abu Musab al-Zarqawi: The Jordanian founder of Tawhid wa al-Jihad was dubbed the ”sheikh of slaughterers” after his group’s practice of decapitating prisoners on video in Iraq. He was later adopted by al-Qaeda and became its leader in Iraq until his death in June 2006.
Compiled by Sudeep Doshi