Includes bibliographical references (pages 183-232) and index.

"The so-called Islamic State, or ISIS, has inspired young men and women around the world to commit heinous acts in its name. By the thousands, they have flooded into the Islamic State's vase stronghold in Syria and Iraq, and in nearly every continent they have carried out attacks under its black banner. The Islamic State has become one of the most popular and successful jihadist groups on the planet, surpassing even al-Qaeda. How did the Islamic State attract so many followers and conquer so much land? By being more ruthless, more messianic, and more devoted to empire-building than its competitors. The shrewd leaders of the Islamic State combined two of the most powerful yet contradictory ideas in Islam--the return of the Islamic Empire and the end of the world--into a mission and a message that shapes its strategy and inspires its army of zealous fighters. They have defied conventional thinking about how to wage wars and win recruits. Even if the Islamic State is defeated, jihadist terrorism will never be the same. Based almost entirely on primary sources in Arabic--including ancient religious texts and secret al-Qaeda and Islamic State letters that few outsiders have seen--The ISIS Apocalypse by William McCants explores how religious fervor, strategic calculation, and doomsday prophesy shaped the Islamic State's past and foreshadow its dark future"--