In the decade that has passed since the terrorist attacks of 11 September 2001, many once-obscure people have become celebrities of a sort. Names such as ‘Osama bin Laden’ and ‘Ayman al-Zawahiri’ have become well known, even to people with only a passing interest in the Middle East, terrorism and Islamism. One name that is clearly not part of this group belongs to the person whose ideas and influence form the subject of this book: Abu Muhammad al-Maqdisi. Although this Jordanian radical Islamic ideologue has received some media attention because of the spectacular acts of terrorism by Abu Musʿab al-Zarqawi, a former leader of al-Qaʿida in Iraq and once a student of al-Maqdisi's, he remains virtually unknown to the general public, even in the Middle East. It therefore came as a surprise to many when, in 2006, the Combating Terrorism Center at West Point, New York, published a study of radical Islam that concluded that, contrary to popular perception, the most influential scholar in the world of militant Islamism today was not former al-Qaʿida leader Osama bin Laden or his successor Ayman al-Zawahiri, but precisely this little-known man called Abu Muhammad al-Maqdisi.

It is clear that al-Maqdisi has indeed been an influential ideologue among like-minded Muslims across the world and that his influence goes far beyond simply having been the teacher of al-Zarqawi. His Arabic website (www.tawhed.ws) offers the largest library of jihadi literature on the Internet and his writings have been translated into about a dozen other languages, most of which are available on his English website (www.tawhed.net). Al-Maqdisi is seen as an important ideologue by Islamist movements from Algeria to Indonesia, his works are praised and quoted by radical Muslim scholars across the Muslim world and he has been a prominent scholarly adviser to Jihadi-Salafi groups in the Gaza Strip and the North Caucasus since 2008.