This essay studies the rise, decline, and rebirth of al Qaeda in Iraq (AQI) and its transformation into the Islamic State of Iraq and al-Sham (ISIS). It first examines AQI’s distinctive vision and its defiance of al Qaeda central. Abu Musab al-Zarqawi’s anti-Shiite jihadist perspective, dramatized by AQI’s use of social media, attracted thousands of foreign fighters to Iraq. The Jordanian’s struggle against Shiite apostates and 2006 martyrdom in a US airstrike continues to dazzle young militants. Second, the essay analyzes AQI’s regeneration and metamorphosis into ISIS and its challenge to al Qaeda’s central command. Abu Bakr al-Baghdadi’s refusal to recognize the authority of al Qaeda’s Ayman al Zawahiri and Baghdadi’s violent resistance to reconciliation measures has sparked destabilizing intrajihadist warfare. Third, the essay examines ISIS’s position as it resists attacks by Iraqi regime forces, rebel groups, Kurdish militants, and US-led coalition air strikes. The essay’s concluding observations analyze the parallels and differences between the Armed Islamic Group’s campaign in Algeria in the 1990s and ISIS’s position in Iraq and Syria in 2015.