"He was reading 'The Guns of August'" Sorenson told him, which documented how miscalculation and momentum propelled the nations of Europe into World War I.

WSJ: The Historian's Stories

Tragically, the weapons with which the next war will be fought - an avoidable war brought on by the Diplomacy of September - will make the lethal Guns of August seem like pop-guns by comparison.

CENTERFORSECURITYPOLICY: The Diplomacy of September

In her Pulitzer Prize-winning book, The Guns of August, Barbara Tuchman chronicled how a cascading series of seemingly minor developments led inexorably to World War I and the worst carnage known to man up to that time.

CENTERFORSECURITYPOLICY: The Diplomacy of September