A fixation with the unreliable and misleading metrics of body counts and “kill ratios” has long been identified as one of the flaws in the U.S. military effort in Vietnam. When progress could not be measured by territorial gains, there was a temptation to show that U.S. forces were inflicting unbearable losses on the enemy. A focus on winning hearts and minds produced a different set of problems. How could an invading army measure whether civilians felt secure and were not alienated? In this meticulous study, Daddis reviews the U.S. Army’s search for a winning strategy in Vietnam and its attempts to evaluate its performance. Counterinsurgency operations rely on political effects that are intrinsically hard to measure. As Daddis notes, the search for numerical formulas was a poor substitute for a deep understanding of the operational and strategic environment. Yet perhaps the greatest challenge was political, rather than methodological: once one of the military’s main objectives became convincing an increasingly doubtful American public that victory was possible, could any metric avoid being distorted?