It is incredibly difficult to penetrate the world view of jihadists. While most analysis of jihadism, or Islamic extremism, focuses on military strategies and ideological doctrines, a growing group of scholars today is studying the cultural practices of jihadists. The forthcoming anthology “Jihadi Culture: The Art and Social Practices of Militant Islamists” focuses on “what terrorists do in their spare time,” and argues that “it is impossible to understand jihadism—its aims, its appeal to outsiders, and its durability—without looking into its culture.”

The book defines jihadi culture as “products and practices that do something other than fill the basic military needs of jihadi groups.” The authors describe many of these practices, ranging from poetry, anashid (a cappella chants), jihadist iconography and cinematography to dream interpretation, the cult of martyrs and the production of martyrdom videos, as well as daily religious practices, etiquette, sport and recreational activities.

The scholars who contributed to “Jihadi Culture” focus on the products and practices of al-Qaeda, its various affiliates and associates, and some of the earlier jihadi groups from the 1980s and 1990s. (Although the culture of the Islamic State is also mentioned in some essays, it is such a recent phenomenon that it is not the main focus of most of the research).

Robyn Creswell and Bernard Haykel write about jihadi poetry, arguing that it is the most significant form of cultural production within jihadi groups and that it “provides a window onto the movement talking to itself, as well as to potential recruits. It is in their verse that militants most clearly articulate the fantasy life of jihad.”

Jihadists write poems describing the hardships they endure, winning rhetorical arguments against their critics, elegizing fallen comrades, praising leaders, and memorializing battles. The poetry is often modeled on early Islamic forms.

The authors argue that the poems should be understood as “performances of authenticity” through which jihadists, who come from many different countries, and are engaged in a radical societal project, forge a new group identity for themselves and consciously lay claim to an imagined past.

Jihadi culture doesn’t hesitate to make use of new technology and contemporary style: posters glorifying mujahideen are directly inspired by comic books, and ISIS propaganda films with high production values are “presumably aimed at capturing a new generation of consumers accustomed to high-resolution video games, TV, and Hollywood movies.” Yet jihadists continually evoke a mythical history and invent a pure tradition to which they claim to be returning. The Islamic State’s instantly recognizable flag is a good example of this: it supposedly recreates a seal used by the Prophet, and its purposely handwritten-looking script suggests a return to a pre-modern era. Yet the flag also represents a clever act of global branding that is unquestionably of our time.

Islamic extremists believe Islam forbids music. But they have embraced the nasheed, a genre popularized by Islamists in the 1970s, which is a chant unaccompanied by instruments. It is the most common soundtrack in jihadi videos. At first, jihadi groups simply took existing anashid and used them as soundtracks; eventually they began composing and recording their own. Scholars suggest that jihadists overcame any doctrinal reservations because of the power of these chants to supplement formal indoctrination with “the potency of music to forge interpersonal bonds and emotionally impact listeners,” as scholar Jonathan Pieslak writes. The American-Yemeni jihadi leader Anwar al-Awlaqi wrote that a good nasheed “could reach an audience that you could not reach in a lecture or a book.” Several accounts of suicide operations suggest jihadists listen to anashid to strengthen their morale in the hours before carrying out attacks.

The essays in “Jihadi Culture” contain fascinating and startling insights into the lives and beliefs of jihadists. They believe that the bodies of martyrs don’t decompose but rather emanate pleasant smells. They take dreams and dream interpretation very seriously, and frequently link their decisions to join a militant group and to undertake particular military operations to a certain revelatory or premonitory dream. Many jihadists weep in a public and ostentatious way—when they are moved by the beauty of the Quran or by Muslim suffering, or out of disappointment at being denied a chance to fight or become martyrs. (Yet within jihadi culture the correct response to a comrade’s death is to rejoice.)

Research has suggested that many jihadists, especially those from the West, have a low level of religious education, which has led commentators to dismiss their piety as a façade. In his chapter on the daily non-military practices of radical Islamists, Thomas Hegghammer finds that “they take ritual observance very seriously.” Many jihadists wake up in the middle of the night to pray, and also pray in the middle of battles, putting themselves in some danger. Hegghammer found that jihadists “mostly did what other Sunni Muslims do, only with greater frequency and intensity.” The jihadists’ most striking departure from the mainstream is their embrace of unlimited violence to pursue their goals.

Research on jihadi culture, Hegghammer argues, “should interest scholars from a broad range of disciplines, including Islamic studies, anthropology, sociology, psychology, political science, and even economics.” It is “highly policy-relevant, because it can shed new light on why people join extremist groups and why some groups and movements survive longer than others.”

It also raises many questions worth studying. “Why is it that most-wanted terrorists spend time on poetry and dream interpretation when they could be training or raising funds? […] What is the role of jihadi culture in individual radicalization, and which elements of jihadi culture are more salient in this regard? If jihadi culture does affect behavior, do leaders manipulate or curate their group’s culture for strategic benefit?”

Hegghammer advances a few preliminary theories. One is that familiarity with jihadi culture is a way for recruits to signal their trustworthiness and commitment. Another possibility is that “cultural products and practices serve as emotional persuasion tools that reinforce and complement the cognitive persuasion work done by doctrine.” Producing and consuming poetry, films and chants may be an important part of the “jihadist lifestyle,” a source of pleasure and bonding that helps explain these groups’ recruitment successes and appeal.

I first learned about this project a few years ago, and when I wrote about it then some readers were horrified by the thought that we should “understand” jihadists rather than simply eliminate them. Learning about jihadi culture can be uncomfortable, because it inevitably humanizes people who hold shocking beliefs and carry out abhorrent actions. Acknowledging the humanity of such people is more troubling than just dismissing them as monsters.