Stephanie Kwolek, the inventor of Kevlar, died on 20 June at the age of 90. She was a qualified chemical engineer when she joined a research team at DuPont in 1946. The company was at the forefront of the development of new polymers and plastic materials. Kwolek was tasked with researching the uses of polymers and low temperature condensation processes to develop new fibres strong enough to reinforce car tyres.  In her research she discovered an unusual molecular formation in the polymer she was developing. Initially, her peers dismissed the irregularity, but she persevered and found that this new material was much stronger than steel. This was patented in 1963 as ‘Fluorine Containing Aromatic Polycarbonamides’ as a ‘novel and useful class of polycarbonamides’.  From the beginning these fibres were able to withstand great extremes of heat and cold and were developed into Kevlar, the very strong, fireproof, yet lightweight, and bulletproof fabric. Today we take bulletproof vests worn by the police and combat forces for granted, these are made from Kwolek’s Kevlar and one million are now in existence around the world. They have been refined and styled to fit different sizes and tailored for men and women and Kevlar is also used  in fire-fighters’ boots, bulletproof helmets, fibre optic cables, car braking systems and skis as well as in space vehicles and for landings on Mars. During her career, Stephanie Kwolek was involved in 28 patents for Dupont, some as the outright inventor and many as part of a research team. She seems to have been modest about her achievements, but there is no doubt that her attention to detail created something extraordinary.