First volume in Decisive Battles of the 21st Century. From the Executive Summary:

On October 7, 2001, U.S. aircraft began bombing the training bases and strongholds of Al Qaeda and the ruling Taliban across Afghanistan. The leaders who sent murderers to attack the World Trade Center and the Pentagon less than a month earlier and the rogue government that provided them sanctuary were running for their lives. President George W. Bush’s expression of America’s desire to get Osama bin Laden “dead or alive” seemed about to come true.

Two months later, American civilian and military leaders celebrated what they viewed as a lasting victory with the selection of Hamid Karzai as the country’s new hand-picked leader. The war had been conceived as a swift campaign with a single objective: defeat the Taliban and destroy Al Qaeda by capturing or killing bin Laden and other key leaders. A unique combination of airpower, Central Intelligence Agency and special operations forces teams and indigenous allies had swept the Taliban from power and ousted Al Qaeda from its safe haven while keeping American deaths to a minimum. But even in the initial glow, there were concerns: The mission had failed to capture or kill bin Laden.

This failure and its enormous consequences were not inevitable.