The Black Swan

A BLACK SWAN is 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 astonishing
success of Google was a black swan; so was 9/11.

- excerpt from the inside flap of

THE BLACK SWAN
The Impact of the HIGHLY IMPROBABLE
Nassim Nicholas Taleb
2007 Random House
ISBN 978-1-4000-6351-2