BY MATTHEW HERBERT

The most striking achievement of the terrorist organization Islamic State in Iraq and Syria (ISIS) is that, unlike other jihadist groups, ISIS actually ruled a piece of territory, a caliphate meant to unite all Muslims under Koranic law.

Its brutal, iconic founder, Abu Musab al-Zarqawi, took his name from his boyhood home, Warrick tells us, Zarqa–a “gritty” industrial town in northern Jordan. His formative experience was in Jordan’s largest prison, al-Jafr, in the burning southern desert.

ISIS might never have come into being had Zarqawi not found refuge in 2002 in a highly unusual place, the Zagros mountains of northern Iraq, nestled among two groups of people who had little love for jihadists–the predominantly secular Kurds and the Shi’ite Iranians, just across the border to the east.

ISIS arose in the “Sunni Triangle,” a restive area west of Baghdad, home to Saddam Hussein’s familial tribe; it made its caliphate’s capital in Raqqa, Syria; and in a stunning blow, it conquered Mosul, Iraq, a city of more than a million people, in one day. At its height, ISIS’s caliphate comprised an area larger than Israel and Lebanon combined, as Warrick reports.

In 2014 and 2015, foreign ISIS volunteers streamed into northern Syria through Turkey in such numbers that Turkey’s southern Hatay Province became infamous as an ISIS way station. Camouflage-clad jihadists openly shopped for combat gear in local military surplus stores.

Given this profusion of geography, how, I wonder, did a Pulitzer Prize-winning book about ISIS come to feature only a single, highly impressionistic map? The story of ISIS is its meteoric rise from secretive terrorist group hiding in safe houses to a functioning army capable of openly controlling territory (and eventually losing it–a part of its history that postdates Warrick’s book).

In most ways Black Flags: The Rise of ISIS is highly commendable. In fact, I don’t even mind that it undeservedly won the Pulitzer, because the story Warrick tells is one that needs wider awareness. If the Pulitzer gave it a push, good. After years of thick books and studies on post-9/11 terrorism and endless analyses of our wars in Iraq and Afghanistan, a presumably weary public still needs to know that our entanglement with Sunni jihadism is not over.

Indeed this is the source of my discontent with the lack of detailed maps in Black Flags. The fact that I knew the places Warrick was describing without looking at a map was a constant reminder that his book seemed to have been written for people like me, with enough background to take in the narrative at speed. It should have been pitched to an audience that hadn’t yet come to grips with the ways 9/11, the Iraq war, the Arab Spring, and the Syrian civil war shaped ISIS in all its unique specificity.

Or maybe I’m over-emphasizing this weakness. A friend of mine who fought against ISIS’s forerunner, al-Qaeda in Iraq, read Black Flags recently as someone who knew the objective facts up close but wanted a big-picture interpretation of what it all meant. Experts, soldiers and the general public alike have been left to wonder whether the “global war on terrorism” begun 20 years ago has come to an end. Black Flags keeps that question front and center even though it does not–cannot–answer it.

Another weakness of the book, which my friend drew out, is the strong impression it gives of a journalist who rushed out a gripping story that should have been more deeply reported. Many developments that clearly called out for deep primary sources were instead given thin washes of secondary source material. Indeed many of the pivotal events described in Black Flags are simply recontextualized quotations from the memoirs of, among others, King Abdullah of Jordan, Army General Stanley McChrystal, and former Secretary of State Hillary Clinton.

And even where the experiences described are intimately reported, there is a disappointing poverty of on-the-scene sources. The descriptions of ISIS’s brutal Sharia enforcement regime, which included horrific public punishments including crucifixions, come from a single witness. Warrick also underexploits the vast trough of information that ISIS published about itself. Not that this material should be taken as reliable narration of ISIS’s history, but the fact that Warrick makes only one glancing reference to Dabiq, ostensibly the caliphate’s newspaper of record, belies a rush to publish. Half the story of ISIS was its own edifice of grand delusion, which deserved a closer look.

All that said, Black Flags is nonetheless a very good book that deserves to be read. It moves fast and keeps the narrative crisp. It’s possible that Warrick judged wisely when he (or his editors) decided to keep it short, at 316 pages. It could have been a better book with 200 more pages, I believe. But what do I know? The more people who read Black Flags the better, and maybe they wouldn’t want to read a “better” book.