A book about al Qaida produced by a British academic is on the best-seller list in the US.
Inside Al Qaida: Global Network of Terror, by Dr Rohan Gunaratna, is the first in-depth account of the origins and workings of the terrorist group.
Dr Gunaratna argues that after being under attack for months in Afghanistan the group is as threatening as it was before September 11.
The Scottish academic - who is a Research Fellow at St Andrews University's Centre for the Study of Terrorism and Political Violence - also says al Qaida offers training and support for guerilla campaigns in the Middle East, Asia, Africa, the Caucuses and the Balkans.
His book also covers what he claims is the clandestine al Qaida network in the West.
The deputy director of the centre, Dr Magnus Ranstrop, said: "The author has crafted a masterful but frightening picture of al Qaida's global research and the degree of clear and present danger posed by its leadership and its foot soldiers."