Josef Stefan: His life and legacy in the thermal sciences

This paper discusses the life of Josef Stefan, namesake of both the Stefan-Boltzmann constant, used in radiation heat transfer, and the Stefan number, the dimensionless variable used in solid-liquid phase change processes. Stefan was also the first to accurately measure the thermal conductivity of gases. He was a beloved teacher and a mentor to Ludwig Boltzmann. Although Stefan made broad and seminal contributions to the thermal sciences, he is not a widely known figure.