In the last three months of 2001 Osama bin Laden is probably the most talked about man on the planet. The reason is the horrifying events of September 11, when four civil airliners taking off from US airports are hijacked by terrorists on a suicide mission. Two of them are flown into a world-famous symbol of capitalist achievement, the twin towers of the World Trade Centre in downtown Manhattan. A third is deliberately crashed into the Pentagon, the US military command post in Washington. A fourth, destined perhaps for the White House, crashes in a field in Pennsylvania after passengers attempt to overwhelm the hijackers.

The deaths in New York number nearly 3000 (the eventual official figure is 2823), with travellers in the planes and the victims in the Pentagon adding several hundred more. The entire terrorist attack, the largest ever carried out, is known by an abbreviation of the day and the month, 9/11

It soon becomes evident that the hijackers were Arab Muslims, making it probable that the horrors are linked with the al-qaeda terrorist network set up and funded by the rich Saudi dissident Osama bin Laden. Documentary and video evidence is subsequently found, confirming his involvement and his pleasure at the outcome.

The USA has not been attacked on its home territory at this level of aggression for nearly two centuries (since the British burnt the Capitol in 1814). President Bush reacts with the most expensive manhunt ever launched - the Afghan war of 2001. And the public discover the story of Osama bin Laden.

Born in Saudi Arabia in 1957, into a wealthy family in the construction business, he inherits considerable wealth while still a young man - and subsequently greatly increases it by his own business acumen. But from his twenties his main interest is in fighting what he perceives to be the enemies of Islam.

This takes him to Afghanistan in 1982 to help the mujaheddin in their struggle against the Russian invaders. While there he sets up and funds an organization to train the many Arabs who come to join him in the cause. It becomes known as al-qaeda ('the base').

When the Russians pull out of Afghanistan, in 1989, bin Laden returns to Saudi Arabia. But he soon finds a new affront on his home territory. In 1990, after the Iraqi invasion of Kuwait, the government allows US troops to be stationed on Saudi soil - and even to remain for security after the war. Bin Laden regards their presence as polluting the region where Islam was first preached. He begins to campaign against the ruling Saudi family and is soon expelled. He moves in 1991 to Sudan, where he continues to develop his al-qaeda network.

During the next five years there are a series of terrorist attacks against US targets - a bomb at the World Trade Centre, an ambush in Somalia (both 1993), a truck bomb at a military base in Saudi Arabia (1995).

The Clinton administration, suspecting the involvement of bin Laden, persuades the Sudanese government to expel him. In 1996 he moves (with three wives, ten children and many followers) to Afghanistan, where he declares a holy war against the USA - and builds more al-qaeda training camps. A close alliance develops with the Taliban leadership. Meanwhile bin Laden's highly trained and well-equipped followers (often known as the Arab Afghans) become a power in the land probably as great as the official Afghan army.

The events of September 11 cause the US administration to demand the extradition of bin Laden as their prime suspect for the atrocity. The Taliban leader, Mullah Omar, refuses. And a new Afghan war begins.

After the war the Taliban are no longer in power, and both Mullah Omar and Osama bin Laden have vanished. Many lesser members of al-qaeda have been captured and are interrogated, early in 2002, for news of their leader.

It is thought at the time that he may be dead, killed in the heavy US bombardment of al-qaeda positions. But he has slipped through the mountain passes into northwest Pakistan, where his cause has many followers and the prevailing law is that of local warlords. He subsequently issues occasional audio and video tapes to be broadcast to the world. Meanwhile the danger to western nations is that graduates of the al-qaeda camps appear to be widely spread, and the organization operates as a network of semi-independent cells. Subsequent terrorist atrocities suggest that fanatics trained by bin Laden remain eager to continue his ruthless programme regardless of his own fate.

Finally, in 2011, US intelligence agencies have gathered enough evidence to suggest the strong probability that bin Laden is hiding in a compound in the Pakistani town of Abbottabad. On May 2 two helicopters take off from Afghanistan and fly low through Pakistan without the knowledge of the Pakistan government. Landing within the compound, tjhey find bin Laden and his family on the second floor of the main building. He is shot and within 24 hours, to avoid any danger of a martyr's shrine, his body is buried at sea.