Just as U. S. soldiers and diplomats pulled out of Afghanistan, supposedly concluding their role and responsibility in the two-decade conflict, the country fell to the Taliban. In The Long War, award-winning BBC foreign correspondent David Loyn uncovers the political and military strategies-and failures-that prolonged America's longest war.

Three American presidents tried to defeat the Taliban-sending 150,000 international troops at the war's peak with a trillion-dollar price tag. But early policy mistakes that allowed Osama bin Laden to escape made the task far more difficult. Deceived by easy victories, they backed ruthless corrupt local allies and misspent aid.

The story of The Long War is told by the generals who led it through the hardest years of combat as surges of international troops tried to turn the tide. Generals, which include David Petraeus, Stanley McChrystal, Joe Dunford and John Allen, were tested in battle as never before. With the reputation of a "warrior monk," McChrystal was considered one of the most gifted military leaders of his generation. He was one of two generals to be fired in this most public of commands.

Holding together the coalition of countries who joined America's fight in Afghanistan was just one part of the multi-dimensional puzzle faced by the generals, as they fought an elusive and determined enemy while responsible for thousands of young American and allied lives. The Long War goes behind the scenes of their command and of the Afghan government.

The fourth president to take on the war, Joe Biden ordered troops to withdraw in 2021, twenty years after 9/11, just as the Taliban achieved victory, leaving behind an unstable nation and an unforeseeable future.