In retrospect, the political and cultural climate in the early '60s seems both a time of innocence and also like a sultry, still summer day in the Midwest: an unsettling calm before a ferocious storm over Vietnam, which was not yet an American war.

Nations without a past are contradictions in terms. What makes a nation is the past, what justifies one nation against others is the past, and historians are the people who produce it.

The sad truth is that without complex business partnerships between African elites and European traders and commercial agents, the slave trade to the New World would have been impossible, at least on the scale it occurred.

History will tell you that borders are not inevitable, they hardly existed at the end of the 19th century.

I believe history will come to view 9/11 as an event on par with November 22, 1963, the date on which John F. Kennedy was murdered, cutting short a presidency that was growing ever more promising. Dreams died that day in Dallas; it is easy to imagine the 1960s turning out rather differently had President Kennedy lived.

Just by my home is an entrance to the sewers they used in the Warsaw uprising. I grew up knowing people died down there. Warsaw was once a battleground; then it became a morgue. It's a city littered with ghosts. And that never left me.