The Power Of Doors, Gates, Locks And Keys

The gates of Harvard are an icon, fencing in one of the most elite universities in the world. But — while they may gate in great minds — they also keep out all others, including protesters of 2011's "Occupy" movement, when administrators locked the gates.

Gates, doors, locks and keys are all powerful metaphors for security, according to Daniel Jütte, historian of early modern — and modern — Europe, and author of "The Strait Gate: Thresholds and Power in Western History."

His book, he says, is a "history of the hopes and anxieties that Western culture has attached to them."

Daniel Jütte, author of "The Strait Gate: Thresholds and Power in Western History."