To the extent that there is such a thing as a normal jihadist group, ISIS is not one. Coverage of what makes ISIS different has largely focused, with reason, on its violence and brutality. But there's something else that makes the group unusual that has gotten less attention: ISIS says, quite openly, that its ultimate mission is to bring about the apocalypse.

The ISIS Apocalypse, a forthcoming book from Brookings scholar Will McCants, examines the history, theology, and strategy behind ISIS's obsession with the end times.

For McCants, it's not obvious whether ISIS actually believes that they'll help end the world, or if they're just using this idea as part of their recruiting pitch to impressionable young men. But that's almost beside the point: prophecy, including the belief in an apocalypse, has come to play an important role in the group's strategy actions. This, McCants argues, has clear implications for how ISIS thinks — and how it acts.

In advance of the book's September 22 publication, McCants and I sat down to discuss what he found and what it means. What follows is a transcript of our conversation, edited for length and clarity.

Zack Beauchamp: What does ISIS think about the apocalypse?

Will McCants: You have to judge them by their rhetoric; it's never clear to an outsider whether they believe what they say or not. But based on their rhetoric, they believe that the final apocalyptic battles with the infidel are swiftly approaching, but are not quite here yet.

That makes them unusual for jihadist groups, at least in the al-Qaeda mode, because the older generation really played down apocalyptic thinking. They use the language of Islamic prophecy about the end times, but they envision it happening far in the future.

The Islamic State is different. It foregrounds the prophecies and uses them, at the very least, to recruit people. At most, it has an influence on their strategic thinking.

ZB: Is there a generally accepted way in which the apocalypse goes down in this tradition? Who are the main actors?

WM: In the book, I translate the prophecies so people can evaluate them for themselves and see how they compare with one another. Most Islamic prophecies about the end times are not actually found in the Koran. The Koran is very vague about what will happen preceding the Day of Judgment; most of these prophecies are found in words that are attributed to Mohammed in later literature.

There are hundreds, if not thousands, of prophecies. Many of them are contradictory or don't line up in an easy chronology of what's going to happen. People interested in the prophecies spend a lot of time trying to reconcile the contradictions and line them up into a coherent timeline.

In general, many of the prophecies envision a growing conflict between the "true Muslim" and other Muslims. So there's a sectarian conflict between a small band of true believers and then a wider group of "bad Muslims." This sectarian conflict will play out specifically in Syria and in Iraq.

Over time, the conflict will widen and include a war with the infidel — which will take place in Syria and around Jerusalem. The Muslim savior figure, the Mahdi, will appear in Mecca and join the Muslim army against the infidel. Jesus will appear at some point and will fight on the side of the Muslims against the antichrist, who is prophesied to appear in various locations.

After the victory of the Muslims over the infidel, they believe the world is eventually overrun by Gog and Magog, who will be familiar to folks who know biblical literature — basically wild men who will destroy the world.

And then we finally get down to the fire-and-brimstone stuff. The universe explodes, and all of the remaining sinners are gathered before God to face judgment at the final hour.

ZB: Which prophecies does ISIS specifically care about?

WM: ISIS focuses a lot of the prophecies that have to do with Syria and Iraq. Many of these prophecies were written as propaganda, actually, in early Islamic history. One side or another would write a "prophecy" about their inevitable victory and the inevitable defeat of their enemy, and, over time the memory of where these prophecies came from would be forgotten. Many of them have been attributed to Mohammed to give them later authority.

Because much of early Islamic history happened in modern Syria and Iraq, many of the place names in these prophecies resonate with conflicts today. So when you have major military conflicts in these geographic locations, they lend themselves to being interpreted by prophecy.

You have specific locations that are mentioned in Syria — Damascus, areas around Damascus, and a tiny area up north just outside of Aleppo called Dabiq. The Dabiq prophecy in particular has attracted a lot of the Islamic State's attention. It identifies the tiny town and the meadow outside of it as the location of one of the final battles with the infidel.

ZB: And you think the Dabiq prophecy and other, similar ones actually shape their actions? That this isn't just something they talk about?

WM: Certainly in the case of Dabiq it does. Their English-language journal was named Dabiq; they also went out of their way to capture the village, even though it's militarily unimportant.

You can say they capture the piece of territory because they believe the prophecy, or you can say they capture the territory because they want others to believe the prophecy. But either way, they captured the territory. So the political impact [of the prophecy] is the same.

ZB: So do ISIS's leaders actually believe their apocalyptic rhetoric? Or is this all for propaganda purposes?

WM: This is something I go into a lot in the book, and I don't want to disclose all of my discoveries. But I can tell you generally that the leadership of the early Islamic State [2006 to 2010] seemed to have really believed these prophecies and acted accordingly.

As for the later leadership of the Islamic State, under [current caliph] Abu Bakr al-Baghdadi, the extent to which prophecy drives their behavior is unclear. I wouldn't draw a straight line between prophecy and scripture and what the Islamic State is doing.

But I can tell you this: whereas the early Islamic State really focused on the coming of the Mahdi, the later Islamic State really focuses on the institution of the caliphate as a fulfillment of prophecy. That's a major distinction between the first Islamic State and the second.

ZB: How much does ISIS's sense of apocalyptic destiny matter to its international recruiting? Do foreign fighters come to Syria and Iraq because they think they're going to end the world?

WM: We have seen a number of reports from journalists who talk to foreign fighters streaming into the Islamic State's territory, and they are telling these journalists that they are coming because they believe the end times are swiftly approaching. They want to join the prophesied caliphate as it prepares to fight the final battle against the infidel.

It's a major part of the Islamic State's recruiting pitch. And a certain segment of the foreign fighter population is responding to it. You wouldn't want to say everyone; people have a lot of different reasons for why they go, and they're able to cite a number of grievances. But we can say, from interviews with fighters, that apocalypticism does drive a certain portion of them to join the organization.

ZB: You've seen Muslim authorities around the world responding to ISIS by saying, "They don't speak for us, they don't represent us." Does it matter that these leaders are criticizing ISIS's theology, and would it matter if they decried its seemingly dubious approach to the apocalypse more specifically?

WM: I would say no. I don't think they really put much of a dent in the Islamic State's recruitment. Perhaps they help in the margins, and I put them in the category of "things that are harmless and perhaps worth doing," but I don't think they're going to make a big difference in diminishing the Islamic State's appeal.

That's because they're not trying to appeal broadly to the Muslim masses. Islamic prophecies of the end times are found in Islamic scripture, but many Muslims don't pay attention to them.

ISIS is trying to appeal more narrowly to young people who are attracted to violence and who seek to play a role in something larger than themselves. Whether that be the reestablishment of the caliphate, the apocalyptic end times drama — that's the Islamic State's recruiting pitch.

ZB: You've mentioned al-Qaeda a few times. How does ISIS's theology shape their relationship with AQ and other militant groups?

WM: The fundamental reason the Islamic State is having a conflict with al-Qaeda is that it considers itself an actual state, and it's bristled at al-Qaeda's efforts to treat it otherwise. That's both about theology and strategy.

I would also trace their hostility to others, such as Syrian rebels, back to this self-identity as an actual state. ISIS believes it should not be treated like any other insurgent group; this is what brought it into a lot of other Sunni insurgent groups in Iraq and what brought with anyone who defied it in Syria over the past few years.

ZB: Have any other groups that controlled large chunks of territory ever had this kind of apocalyptic worldview?

WM: I can cite medieval precedent for this, for sure.

The historian in me is hesitant to say we've never seen anything like this in the modern period. But for Sunni jihadist groups, it is unusual to have an insurgency of this size controlling so much territory, claiming itself to be the fulfillment of prophecy, and using an apocalyptic sales pitch to attract recruits. I can't recall a group among Sunni jihadists in the modern period.

There have certainly been medieval Muslim groups that have framed their rise to power as a fulfillment of prophecy. But I can't think of comparable, successful groups in the modern period that have done it.

Incidentally, you can certainly rebel as a Muslim without framing things in apocalyptic terms. As I've said, most jihadists don't do it, and even in medieval times most groups cited more mundane reasons or non-apocalyptic theological reasons.

Apocalypticism can certainly be a powerful tool for attracting recruits and justifying what you're doing. But if you disappoint apocalyptic expectations, it can easily work against you.