The believer: How an introvert became the leader of the Islamic State

Since Baghdadi’s sudden emergence from obscurity in 2014 as the monster who ordered and broadcast on YouTube the beheading and even burning alive of those he deemed his enemies, news articles and books have traced his radicalization back to the U.S. invasion of Iraq in 2003. Although the American invasion fed the fire and enabled it to spread, in fact, his radicalization began much earlier, ignited by an unlikely but highly volatile mixture of fundamentalism, Saddam Hussein’s secular totalitarianism, and his own need to control others.
...If Baghdadi’s life is a cautionary tale, it is about the danger of creating the chaos that allows men like him to flourish.