Nassim Nicholas Taleb, expert on risk and randomness, discusses "The Black Swan: The Impact of the Highly Improbable," presented by Harvard Book Store. Nassim Nicholas Taleb defines a "black swan" as a highly improbable event with three principal characteristics: It is unpredictable; it carries a massive impact; and, after the fact, we concoct an explanation that makes it appear less random, and more predictable, than it was. The success of Google was a black swan; so was 9/11. Black swans underlie almost everything about our world, from the rise of religions to events in our own personal lives. How can this phenomenon be better recognized and understood? This lecture contains strong language.This talk was taped on May 19, 2010.