It is April 2003. American forces have taken Baghdad and are now charged with winning hearts and minds. But this vital tipping point is barely recognized for what it is, as a series of miscalculations and blunders fuels an already-simmering insurgency intent on making Iraq the next graveyard of empires.

In dazzling and propulsive prose, Brian Van Reet explores the lives on both sides of the battle lines: Cassandra, a nineteen-year-old...