This is a somber and angry book. As previewed in his subtitle, David Kilcullen argues that, in all but one significant respect, 15 years of Western counterterrorism efforts have failed. He acknowledges that further attacks on the scale of September 11, 2001, have been prevented, both by enhancing domestic security measures and diminishing the capacity of al-Qaeda (AQ) and other groups to organize complex, expensive, and distant operations. “The disaggregated, atomized terrorist cells and radicalized individuals of today can mount a larger number of smaller, less sophisticated and far less damaging attacks than the centrally organized AQ of 2001,” he writes. “If that were the only outcome [of Western policies], you would have to call the past fifteen years a resounding success.”

But such a conclusion, Kilcullen insists, ignores the immense damage being done in Afghanistan, Iraq, Syria, Yemen, Libya, Nigeria, Mali, Somalia, Kenya, and Pakistan by al-Qaeda, the Islamic State of Iraq and the Levant (ISIL), and affiliated groups that Western policy has allowed to proliferate. He thus maintains that the “Blood Year,” starting with the fall of Mosul in June 2014, represents “nothing less than the collapse of the Western counterterrorism strategy as we’ve known it since 2001.”

Kilcullen acknowledges that disengaging from the Middle East by focusing on domestic security would be cheaper and perhaps adequately effective in limiting attacks on the American and European homelands. He argues against such a response, however, for two reasons. First, Western publics would find themselves living in police states, forced to accept ever more restrictions on freedom and intrusions on privacy. Second, withdrawal from the Middle East would collapse the broader international system that depends on American leadership and upon which the security and prosperity of the United States in turn depends.

David Kilcullen has advised on and participated in Western counterterrorism (CT) efforts nearly continuously since 2003, first as an Australian army officer and then as an American government official and a prolific author. His latest work offers a critical review of Western—primarily American—CT policy since 9/11, as well as a detailed account of the rise of ISIL. It concludes with his recommendations for American strategy going forward.

In his preface, Kilcullen insists that this is neither a book about ISIL nor a comprehensive history of the post-9/11 war on terrorism, but rather “a personal account by a mid-level player.” These denials should not be taken too seriously. There is enough first-person reminiscence in the book to substantiate Kilcullen’s abundant credentials to recount, analyze, and recommend as he does, but these personal vignettes take up little space and rather serve as introductions to narrative accounts, with commentary, on the evolution of terrorist movements in the Muslim world since September 11, 2001, and the course of Western efforts to combat them.

The “Blood Year” of the title opens with the fall of Mosul and extends into, and as a practical matter through, 2015, concluding with the November 13 ISIL-inspired attacks in Paris. In the preface, Kilcullen notes that his academic field is not terrorism, but rather guerrilla and unconventional warfare. He thus devotes the bulk of his attention to the insurgent and even to the conventional military threat posed by ISIL and the Western military responses. He also, however, covers quite effectively the evolution in terrorist attacks and counterterrorist operations in Western homelands.

The book contains excellent detailed descriptions of several set-piece battles that marked this year, including the ISIL seizures of Mosul and Ramadi, its loss of Tikrit, and the seesaw battle of Kunduz between the Taliban and Afghan government forces. These accounts make clear how formidable these movements have become and how distinct the challenge they represent is from the underground network of conspiratorial cells that characterized the al-Qaeda of old.

The book’s coverage is neither comprehensive nor entirely consistent. It is mostly about the decline of al-Qaeda and the rise of ISIL, with a focus on Iraq and Syria, but also addresses Tunisia and Libya. There is also extensive discussion of Afghanistan, mostly as regards the Taliban, although al-Qaeda and ISIL both make cameo appearances there. On the other hand, al-Shabaab in Somalia, an al-Qaeda affiliate, gets only passing mention, and Boko Haram in Nigeria, an ISIL franchise, gets none at all. This selection reflects Kilcullen’s extensive field experience in Iraq and Afghanistan, and in and around Syria. The book is stronger for concentrating on the areas the author knows best, rather than straining for universal coverage.

Kilcullen is highly critical of the policies of both the Bush and the Obama administrations. Beginning in 2003, while still in Australia, he favored a strategy he labels “disaggregation.” This involves decapitating the al-Qaeda leadership, cutting the links among its affiliates and imitators, and then addressing each of these within its own unique context. The Bush administration’s so-called “Global War on Terror” also attacked al-Qaeda’s central nervous system, but it tended to take an undifferentiated approach to the wider range of violent extremist movements in the Muslim world.

Kilcullen likens Bush’s invasion of Iraq to Hitler’s assault on the Soviet Union, arguing that in both cases the result was to open an unnecessary second front, diverting attention and resources from what should have been the main fight. He also criticizes the administration’s initial small-footprint approach to post-conflict stabilization in both Iraq and Afghanistan, which gave space to the emergence of violent resistance movements.

The Obama administration receives equal criticism from Kilcullen for withdrawing American forces from Iraq and for seeking to do the same in Afghanistan. He contrasts Obama’s vacillation over Syria with Russian President Vladimir Putin’s decisive action there. While these are familiar criticisms, Kilcullen provides enough detail to lend them additional weight. His analysis of Russian policy is by turns admiring and condemnatory. He posits three options for American policy in responding to Russia’s expanded role in Syria: leave the problem to them; compete with Moscow for influence; or cooperate. Kilcullen recommends the third option, a view which the Obama administration seems to have adopted as well.

He advocates a middle path between the advise, assist, and aerial bombardment strategy of the Obama administration and the overrun, occupy, and govern approach adopted by the Bush administration in Iraq. Specifically, he recommends a reduced reliance on drone strikes, which Kilcullen has long warned may create more terrorists than they kill, combined with the commitment of “a moderately larger number of ground troops” in a campaign to drive ISIL out of its territorial base in Iraq and Syria. He also argues for greater Western pressure on its Middle Eastern partners for reform and democratization.

Though Kilcullen opposes an open-ended commitment to occupation and reconstruction, he does not offer a view as to how the areas liberated from ISIL would be governed. He recognizes that taking Mosul and Raqqa will not end the threat from ISIL—or an even worse successor—unless this territory can be held. One can imagine some equilibrium being achieved between Sunnis, Shias, and Kurds in Iraq within the framework of the existing Iraqi constitution, but it is hard to believe that peace can be consolidated in Syria without some sort of stabilization force.

Kilcullen labels his preferred strategy “active containment.” This seems something of a misnomer, as he clearly advocates a military campaign to close down the ISIL caliphate in Syria and Iraq. However, he also envisages “a multigenerational struggle against an implacable enemy,” warning that the level of violence we are seeing in the Middle East is “the new normal,” not some transitory aberration. Kilcullen can certainly not be charged with undue optimism. His diagnosis is dire, but his prescriptions are comparatively restrained and might well appeal to the next U.S. administration.