At first sight, Black's sheets look like monotonous arrays of numbers. They were, however, beautifully designed for their intended role in "distributed cognition" (Hutchins 1995a,b). Black included what options traders using the Black-Scholes-Merton model needed to know, but no more than they needed to know There was virtually no redundant information on his sheets hence the sheets' easy portability. Black devoted particular care to the crucial matter of the estimation of volatility.

Donald MacKenzie, An Engine, Not a Camera, loc. 720