John M. Prausnitz is a professor of chemical engineering at the University of California, Berkeley, a position he has held since 1955. Dr. Prausnitz is responsible for many of the activity coefficient models used for the design of major chemical plants. He was born on January 7, 1928 in Berlin, Germany. Prausnitz completed his PhD in 1955 with a dissertation “Liquid-Phase Turbulent Mixing Properties” at Princeton University. Prausnitz currently is professor emeriti of the graduate school of the University of California, Berkeley, department of chemical and biomolecular engineering. In 2003, he received the National Medal Of Science.