On 23 October 2014, Abdelaziz Kuwan, a second-year student of Islamic studies at a religious college in Saudi Arabia, was shot dead by a Syrian government sniper in the al-Hawiqa district of the eastern Syrian town of Deir Ezzor. Nearly three years earlier the teenager, a high-school dropout from Bahrain, had defied his parents and flown to Istanbul, then crossed into the Syrian province of Aleppo. He fought for moderate rebel factions before their corruption and inefficacy drove him into the arms of the Islamists. After some time spent with Ahrar al-Sham, a powerful faction that has been backed by various Gulf states, he switched to Jabhat al-Nusra, the affiliate of al-Qaeda in Syria. After a brief spell back at home, he returned to the conflict but this time joined the Islamic State of Iraq and Syria (ISIS), which became known simply as the Islamic State (IS) after its leader, Abu Bakr al-Baghdadi, declared a caliphate. Kuwan rose to become a security official running three towns. He participated in executions and repeatedly raped a captive girl from the Yazidi minority whom he had been given as a sabiyya (sex slave) as a reward for his role in battles against Kurdish forces. Kuwan now called himself Abu al-Mutasim, after the eighth caliph of the Abbasid dynasty, which had presided over much of the ‘golden age of Islamic civilisation’ and one of the greatest historical empires in the 8th and 9th centuries. ‘I came … seeking martyrdom,’ Kuwan told Michael Weiss and Hassan Hassan, the authors of ISIS: Inside the Army of Terror, a few months before his death. 

Like al-Qaeda in its time, the emergence of this new enemy – IS, ISIS, ISIL or, more pejoratively, Daesh – has prompted a spasm of publishing. Happily, unlike with al-Qaeda a decade or so ago, there are lots of extremely competent experts around to help us understand the hows, whys