From one of the most important army officers of his generation, a memoir of the revolution in warfare he helped lead, in combat and in WashingtonWhen John Nagl was an army tank commander inthe first Gulf War of 1991, fresh out of West Pointand Oxford, he could already see that Americasmilitary superiority meant that the age ofconventional combat was nearing an end. Nagl wasan early convert to the view that Americas greatestfuture threats would come from asymmetricwarfareguerrillas, terrorists, and insurgents.But that made him an outsider within the army;and as if to double down on his dissidence, hescorned the conventional path to a generals starsand got the military to send him back to Oxford tostudy the history of counterinsurgency in earnest,searching for guideposts for America. The resultwould become the bible of the counterinsurgencymovement, a book called Learning to Eat Soup witha Knife.But it would take the events of 9/11 andthe botched aftermath of the Iraq invasion togive counterinsurgency urgent contemporaryrelevance. John Nagls ideas finally met their war.But even as his book began ricocheting aroundthe Pentagon, Nagl, now operations officer ofa tank battalion of the 1st Infantry Division,deployed to a particularly unsettled quadrantof Iraq. Here theory met practice, violently. Noone knew how messy even the most successfulcounterinsurgency campaign is better than Nagl,and his experience in Anbar Province cementedhis view. After a years hard fighting, Nagl wassent to the Pentagon to work for Deputy Secretaryof Defense Paul Wolfowitz, where he was tappedby General David Petraeus to coauthor the newarmy and marine counterinsurgency field manual,rewriting core army doctrine in the middle of twobloody land wars and helping the new ideas winacceptance in one of the planets most conservativebureaucracies. That doctrine changed the course oftwo wars and the thinking of an army.Nagl is not blind to the costs or consequencesof counterinsurgency, a policy he compared toeating soup with a knife. The men who diedunder his command in Iraq will haunt him to hisgrave. When it comes to war, there are only badchoices; the question is only which ones are betterand which worse. Nagls memoir is a profoundeducation in modern warin theory, in practice,and in the often tortured relationship betweenthe two. It is essential reading for anyone whocares about the fate of Americas soldiers and thepurposes for which their lives are put at risk.