In the years immediately following the 2006 "Surge" of American troops in Iraq, observers of America's counterinsurgency war there regarded the defeat of Al Qaeda in Iraq (AQI) in Anbar Province as one of the strategy's signature victories. With the assistance of American troops, the fractious tribal sheiks in that province united in an "Awakening" that ultimately led to the defeat of the legendarily brutal AQI. The success of the Awakening convinced many that smart, properly resourced counterinsurgency strategies could in fact work. Even more, the episode showed that victory could be snatched from the jaws of defeat. A decade later, the situation in Anbar Province is dramatically different. Beginning in 2014, much of the province fell to the AQI's successor organization, ISIS, which swept through the region with shocking ease. ISIS quickly took Ramadi, the province's main city and the locus of the 2006 Awakening. In The Shadow of Anbar, Carter Malkasian looks at the wreckage to explain why Americans' initial optimism was misplaced and why victory was not sustainable. Malkasian begins by tracing the origins of the Awakening of the sheiks against AQI, which by 2005 dominated the province. Capitalizing on the feuding among traditional sheik leaders, AQI used Islam as a unifying ideology and initiated a reign of terror that cowed opponents into submission. With some help from the US, the sheiks rebounded by unifying against AQI through the Awakening movement. That, coupled with an increased American troop presence beginning in 2006, ultimately led to the defeat of AQI. After chronicling how this transpired, Malkasian turns his attention to what happened in its wake. The US left, and in a naked power play the Shiite government in Baghdad sidelined Sunni leaders throughout the country. AQI, brought back to life by the Syrian civil war as ISIS, expanded into northern and western Iraq in 2014 and quickly found a receptive audience among marginalized Sunnis. In short order, all of the progress that resulted from the Awakening evaporated. Malkasian draws many lessons from what is clearly now a failed experiment at nation building, but a few stand out. US counterinsurgency techniques, no matter how adept, cannot substantially change foreign societies and cultures, particularly ones that have existed for centuries. The American people will not tolerate a long-term US military presence in foreign lands, and what the US builds while there is likely to be temporary. Finally, the debacle reminds us that US military intervention always has a strong potential to generate instability and harm. Ultimately, the US invasion upended society and let sectarian, tribal, and religious dynamics run their course. As The Shadow of Anbar shows, the people of Anbar Province would have been better off if the United States had never invaded Iraq in the first place. Sadly, the residents there are living with the terrible fallout of the 2003 invasion to this day.