New Delhi:
The FBI lists him as a man of unknown height, weight or built, with 13 known aliases and a bounty of 25 million dollars on his head.
This Sunday, June 19, Ayman Muhammad Rabaie al-Zawahiri will celebrate his 60th birthday. His coronation as Osama bin Laden's successor and the new head of the deadly Al Qaeda brings focus on a man who is also known as The Doctor and the Teacher - telling epithets.
For al Zawahiri, with a scholarly mien and thought by many to be the Al Qaeda's brain and ideologue, is also a medical doctor. He is believed to have served as Osama bin Laden's personal physician.
An Egyptian, he founded and for long led a Jihadi organisation, the Egyptian Islamic Jihad, before merging it with the Al Qaeda and emerging as one of Osama's most trusted lieutenants and a powerful force in the terror organisation.
Biographies, and there are many, paint the picture of quiet and shy boy, well-read, growing up in a fraught political environment. He belongs to an upper middle class Egyptian family of doctors and scholars. His father was a pharmacology professor at Cairo University's medical school and his grandfather was the grand imam of Al-Azhar University, a premier center of religious study.
He got involved in Egypt's violent Islamist struggle early, as a 14-year-old.
He is believed to have fought for long in the bid to topple the Egyptian government.
He was among many implicated and arrested after the assassination of Egyptian President Anwar Sadat and after spending about three years in prison, is said to have gone to Saudi Arabia and then to Pakistan to practice medicine.
It was the early 1980s and al Zawahiri met Osama bin Laden then.
al Zawahiri's former lawyer Montasser el-Zayat wrote a book - Al-Zawahiri as I Knew Him - describing his former client as arrogant and intolerant. The new Al Qaeda chief is seen as lacking Osama's charisma but is more cunning, brutal and ambitious. He is believed to be seized by the ambition of giving effect to a terror strike more deadly and more of a spectacle than 9/11 was.
The US wants al Zawahiri for his alleged role in the August 7, 1988 bombings of the United States embassies in Dar es Salaam in Tanzania, and in Nairobi, Kenya. A year later, he was also sentenced to death in absentia by an Egyptian court.
In January 2006, it was reported that al Zawahiri had been killed. It was later reported that he had in fact escaped the US missile raid on the remote Pakistani village that he was in.
(With agency inputs)