Kevlar (PPTA) is a polymer from the group of polyamides, more specifically aramids, from which artificial fibres characterized by high tensile strength are spun. It is widely used, among others, in bulletproof vests and helmets. Kevlar has probably saved the lives of thousands of people so far. It was invented in 1964 by the American chemist of the Polish origin - Stephanie Kwolek. Her parents, John Kwolek (distorted form of "Chwałek") and Nellie Zajdel Kwolek emigrated from Poland in their teens. The father, who had a decisive influence on the development of scientific interests of young Stephanie, died when she was 10. Stephanie studied in a Catholic school, run by nuns, in New Kensington. Afterwards, she majored in chemistry in Margaret Morrison Carnegie College at Carnegie Mellon University in 1946. She wanted to study medicine but due to lack of money she started working as an experimental chemist at DuPont, where she specialized in low-temperature polycondensate forming processes. She headed the team that invented Kevlar in 1964. She is the holder of 28 patents.