Kiyoshi Ito, 93, Mathematician Who Described Random Motion, Dies - Obituary (Obit) - NYTimes.com

His name may not mean much to many, but if you ever took a PHD finance class there is little doubt you will ever forget him. Ito's work played a major role in the development of the Black-Scholes option pricing formula.

From the NY Times: Kiyoshi Ito, 93, Mathematician Who Described Random Motion, Dies - Obituary (Obit) - NYTimes.com:

"Kiyoshi Ito, a mathematician whose innovative models of random motion are used today in fields as diverse as finance and biology, died Nov. 17 at a hospital in Kyoto, Japan. He was 93....Mr. Ito is known for his contributions to probability theory, the study of randomness. His work, starting in the 1940s, built on the earlier breakthroughs of Albert Einstein and Norbert Wiener. Mr. Ito’s mathematical framework for describing the evolution of random phenomena came to be known as the Ito Calculus."