After the attack of 9/11, the FBI discovered at three different locations a document disclosing how the attackers of 9/11 conceived of their violence and prepared for it. The book contains the first scholarly edition of the Arabic text of the Manual of the Attackers of 9/11, along with an English translation and commentary, and studies concerning its context. The nineteen young attackers prepared for their action by spiritual means and this preparation is at the centre of the exercises of the Manual, while the military character of the attack on the economic, military and political centres of today's "paganism" is merely tacitly presumed. Religious practices during the last night turn the young man into a warrior hero. A second stage addresses the perils at the airport. By recitations the "warrior" gets protection in a world dominated by the mighty technology of the "Western Civilization". Finally, at the third stage in the plane, the perpetrator prays to become a martyr. By his readiness to die he gives a practical proof for the existence of a power superior to "Western Civilization". Though it is based on scholarly research, this book is written for a broader audience. It makes a document available that is crucial in understanding the attacks of 9/11. It addresses all the issues debated in public: Is the text a forgery? What is its content? Are suicidal attacks typical for Islam? Does Islam allow such kind of violence? How did the perpetrators perceive of the situation of Islam today? How did they justify the massacre? Were the attackers convicted Muslims? How did the theology of Usama bin Ladin affect the Manual and the attack? Is the "War on terror" an adequate response? The book is of interest for scholars in Islamic and Religious Studies and other disciplines dealing with the issue of 9/11, for journalists and politicians and will serve as textbook in colleges and universities.