From Page 2 of the most recent version of the paper (2006):
Defining a Bubble
Charles Kindleberger (1987) defined a bubble this way:
a sharp rise in price of an asset or a range of assets in a continuous process, with the initial
rise generating expectations of further rises and attracting new buyers—generally
speculators interested in profits from trading rather than in its use or earning capacity. The
rise is then followed by a reversal of expectations and a sharp decline in price, often
resulting in severe financial crisis—in short, the bubble bursts.
