Jihadi Culture offers a sustained and strongly argued corrective to this school of thought by showing that jihadis spend most of their downtime on devotional and recreational practices that are saturated with religious meaning and content. “It may be true that many militants have a non-observant past,” writes Hegghammer, “but my investigation suggests that once they are in a militant group, they take ritual observance very seriously.”

“We should not assume,” Hegghammer adds, “that their belief is less intense just because they know little about theology.” In this, Hegghammer is in agreement with The Atlantic’s Graeme Wood, who has trenchantly argued against the inclination, common among those who downplay the role of religion in the motivation of jihadists, to “confuse duration of piety for depth of piety; religion for religiosity; and, most tellingly, orthodoxy for belief”:

But that is not how religion works, and it is certainly not how ISIS works. Often, the ISIS foreign fighter is newly pious; he arrives at his piety as a Hemingway character once said he arrived at bankruptcy: slowly, then all at once. He is sometimes inconsistent in his practice. (These very failings, and his own self-hatred over them, are often what drive him into ISIS’s redemptive embrace in the first place.) He isn’t learned—most people are not, including most pious people—and he consciously rejects the mainstream. Rejecting it is not error. It is the point.

Jihadi Culture is also a vigorous corrective to tabloid-fueled fantasies of jihadists as bloodthirsty monsters. But is it a little too insistent as a corrective to these fantasies, a little too appreciative of the more soulful aspects of jihadi culture?

On the opening page of the book, Hegghammer writes that “jihadis have a rich aesthetic culture that is essential for understanding their mindset and worldview.” “Rich,” as journalist Andrew Anthony observed in his profile of Hegghammer, is an odd word choice for a culture that is immersed in prohibition, censure, and repression. It is also an unfortunate word choice, because “rich” is a term that morally shades the thing it describes, lending it a positive valence.

This is emblematic of a larger problem with Jihadi Culture: So keen is Hegghammer to correct the tabloid construction of jihadists as one-dimensional brutes that he risks going too far in the opposite direction. This is not to say that he excuses—or, still less, justifies—jihadi culture. But the account he offers is an unmistakably favorable one. It is also consonant with the one that jihadists themselves would like to propagate.

Reading Jihadi Culture, you will find that jihadists “love poetry,” “weep a lot,” “talk regularly about dreams,” “value personal humility, artistic sensitivity, and displays of emotion,” and spend an inordinate amount of time listening to hymns and praying. What you will not read about is the secret, subterranean culture of jihadi groups. Hegghammer makes a big point about jihadists weeping, but it’s likely that they masturbate with as much frequency and ferocity as they weep. There’s probably also a lot of illicit gay sex in jihadi camps. And there’s good evidence to suggest that there’s a fair amount of drug-taking among jihadists. But you won’t read about any of this in Jihadi Culture, because it’s so heavily reliant on the idealized jihadi presentation of self in the form of jihadi personal memoirs.