Once the United States had dealt with the Taliban, it turned its focus to another problematic polity: the regime of Saddam Hussein in Iraq. Alleged – but unproven – links between Saddam's regime and Al Qaeda was a stated reason for the US-led invasion in March 2003. This chapter focuses briefly on Al Qaeda's emergence as a global entity and examines the contention that the terrorist threat it poses is a qualitatively new kind of menace, emanating from a particular type of violent non-state actor. It also examines Al Qaeda's ideological roots, focus and objectives. For Al Qaeda, the aim of 9/11 was not simply to wreak terrible destruction but also to create a global media spectacle, a spectacular advertisement for the organisation and its militant ideological goals. The roots of Wahhabism, a puritanical interpretation of Islam, are found in the ideas of Mohammad ibn Abd al-Wahhab, an eighteenth-century Sunni reformer born in Arabia.