Weiss and Hassan capture the complexity of the Iraqi and Syrian imbroglios that gave rise to the Islamic State (or ISIS) in this thorough and accessible book. ISIS resulted from a merger of sorts between remnants of Iraqi President Saddam Hussein’s Baathist regime and followers of the Shiite-hating Jordanian jihadist Abu Musab al-Zarqawi. The authors suggest that ISIS’ ability to control territory, gather intelligence, and smuggle oil stems mainly from the experience and know-how of the former Baathists. After a revolt broke out in Syria in 2011, the beleaguered president, Bashar al-Assad, abetted ISIS’ spread and even cut deals with the group in order to bolster his claim that his enemies were irredeemable terrorists. While the book does not alter the consensus narrative of the rise of ISIS, it does provide fascinating details about the 2007 anti-jihadist Sunni uprising in Iraq and about jihadist groups’ use of U.S. prisons as recruiting grounds. In this portrait, ISIS emerges as a strategic organization playing a long game; counterterrorist raids and bombing runs will not defeat it.