Book excerpt: In Wars of Ambition, Afshon Ostovar explores America's decline and Iran's rise in the Middle East since 9/11 and through 2023. It examines America's involvement in the region, Iran's counter to it, and how their clash for a new regional order became entwined in a broader, more complex struggle involving multiple regional and foreign powers. In telling that story, Ostovar shows how the battle for the Middle East reflects the politics and dividing lines of an emergent multipolar world.