While family and fortune play defining roles, wars and the economy affect our lives more fundamentally.
In 1960, John O'Hara sent his publisher Bennett Cerf a letter describing the cast of characters in a book he was writing.
O'Hara described them as "the people of my time," men and women too young to be part of The Lost Generation—the generation disillusioned by World War I—but too old to feel part of "The Greatest Generation."
"Everybody can understand a war," O'Hara told Cerf. "But it is not so easy to understand an economic revolution; even the experts continue to be baffled by it; and the people of my time never know what hit them or why."
Millennials are in a companion boat.
They're a generation that won't see anything resembling the luxury and security their parents and grandparents enjoyed.
And they may never know what hit them.
As marketer Mitch Joel advises in his new book, Ctrl Alt Delete, "Accept it: There is no gold watch in your future."
