For the past four years I have been studying what jihadis do in their spare time. The idea is simple: To really understand a community, we need to look at everything its members do. Using autobiographies, videos, blog posts, tweets and defectors’ accounts, I have sought a sense of the cultural dimensions of jihadi activism. What I have discovered is a world of art and emotions. While much of it has parallels in mainstream Muslim culture, these militants have put a radical ideological spin on it.

When jihadis aren’t fighting — which is most of the time — they enjoy storytelling and watching films, cooking and swimming. The social atmosphere (at least for those who play by the rules) is egalitarian, affectionate and even playful. Jihadi life is emotionally intense, filled with the thrill of combat, the sorrow of loss, the joy of camaraderie and the elation of religious experience. I suspect this is a key source of its attraction.

The corridors of jihadi safe houses are filled with music or, more precisely, a cappella hymns (since musical instruments are forbidden) known as anashid. There’s nothing militant about this traditional genre, which dates from pre-Islamic times. But in the 1970s, Islamists began composing their own ideological songs about their favored themes. Today there are thousands of jihadi songs in circulation, with new tunes being added every month. Jihadis can’t seem to get enough anashid. They listen to them in their dorms and in their cars, sing them in training camps and in the trenches, and discuss them on Twitter and Facebook. Some use them to mentally prepare for operations: Ayoub El Khazani, a 25-year-old Moroccan man who attempted a shooting attack on a Paris-bound train in August, listened to YouTube videos of jihadi anashid just minutes before his failed operation.

Anashid are closely related to poetry, another staple of jihadi culture. Across the Arab and Islamic world, poetry is much more widely appreciated than it is in the West. Militants, though, have used the genre to their own ends. Over the past three decades or so, jihadi poets have developed a vast body of radical verse. Leaders from the Islamic State’s spokesman Abu Muhammad al-Adnani to Al Qaeda’s Ayman al-Zawahri often include lines of poetry in their speeches and treatises. Foot soldiers in Syria and Iraq sometimes hold impromptu poetry performances or group recitals in the field.

In any large jihadi group there might be a few people who specialize in composing or memorizing poems. These poets can be anyone from within the movement, men or women of any rank. The Islamic State’s most famous poet is a Syrian woman in her 20s who goes by the name Ahlam al-Nasr, or Dreams of Victory. (While jihadi women generally socialize separately from men, the Internet has allowed women to take a more active part in the movement’s cultural life.) Her most famous collection, “Blaze of Truth,” contains lines such as “Shake the throne of the cross, and Extinguish the fire of the Zoroastrians / Strike down every adversity, and go reap those heads.”