Karl Popper, a fellow Austrian-born academic, advised him to insist on a small additional royalty which he has never regretted.

ECONOMIST: Look and learn

Karl Popper was not always forthcoming about his early life and his early intellectual trajectory may surprise some of his admirers.

ECONOMIST: Non-fiction

The answer comes from the eminent philosopher of science Karl Popper: falsifiability.

FORBES: The Confidence Game

He calls them Black Swans, after the philosopher Karl Popper's observation that only a single black swan is required to falsify the theory that "all swans are white" even when there are thousands of white swans in evidence.

WSJ: Shattering the Bell Curve