In a thrilling dramatic narrative, Pulitzer Prize-winning reporter Joby Warrick traces how the strain of militant Islam behind ISIS first arose in a remote Jordanian prison and spread to become the world's greatest threat.

When the government of Jordan granted amnesty to a group of political prisoners in 1999, it little realized that among them was Abu Musab al-Zarqawi, a terrorist mastermind and soon the architect of an Islamist movement bent on dominating the Middle East. In Black Flags, an unprecedented character-driven account of the rise of ISIS, Joby Warrick shows how the zeal of this one man and the strategic mistakes of Western governments led to the banner of ISIS being raised over huge swathes of Syria and Iraq.