What Americans know about World War I is probably nothing to brag about.
How it started may be a mystery to many. Why the United States got involved, just as befuddling. Baby boomers may know something about the Red Baron because of Snoopy.
And perhaps there's a dim memory of an English teacher reciting verse by melancholy warrior-poets or talking about the war's effect on the namesake character in "The Great Gatsby."
Cambridge historian David Reynolds' most recent book does a remarkable job of explaining why people should know more about the First World War - and why it is so difficult to fully grasp its legacy.
"The Long Shadow" is not simply a history of a century-old conflict.
Reynolds documents its profound impact on world powers as well as on embryonic nations, politics, warfare, the world economy, culture and literature.
The war prompted Sigmund Freud to "rethink his theory of the self," postulating a "drive to destroy" in addition to a drive to procreate.
At its conclusion, President Woodrow Wilson's idealistic dream of making the world safe for democracy fell short.
Millions of men - and women - around the world were granted the right to vote after the war.
"Great dynastic empires" collapsed - czarist Russia, monarchies in Germany and Austria-Hungary, and the Ottoman Empire in the Middle East, North Africa and the Balkans.
But the war also "accelerated the emergence of imperial rivals in the Pacific: Japan and the United States."
"In each case empire and race were tightly entangled," Reynolds writes, "Japan being the only nonwhite great power while America, intensely racist itself, prided itself on not being a colonial empire."
Fascism and communism, two of the world's most virulent political ideologies, expanded with a vengeance in the aftermath.
So, too, did democracy. When the war began, Europe had three republics. After the war there were 13.
One of those new democracies was the defeated and humiliated Germany, although it would soon take a perverted, tragic political turn. The other nine "were states that did not even exist at the start of the war, among them Czechoslovakia, Poland and Yugoslavia."
"The Long Shadow" transcends conventional histories about World War I.
At times, it is almost a psychoanalysis of a world that was profoundly changed by a collective and horrific trauma. But that is no criticism.
It is the kind of book that challenges readers to think.