Charles Proteus Steinmetz (1865-1923), German- American mathematician and electrical engineer. Steinmetz derived mathematical theories to describe alternating current (AC), providing the basis for engineers to increase the efficiency of AC motors. This ultimately led to AC power superseding direct current (DC). Steinmetz was born in Germany but emigrated to America to avoid persecution for his socialist beliefs. Despite congenital dwarfism, hunchback and hip dysplasia, he had a full career, holding several professorships and over 200 patents. This portrait is from the Bain News Service, one of America's oldest news picture agencies, which holds images dating from the 1890s to the 1930s.