Erich Clar (23 August 1902 – 27 March 1987) was an Austrian organic chemist, born in Hřensko, who studied polycyclic aromatic hydrocarbon chemistry. He is considered as the father of that field. In 1941, he authored "Aromatische Kohlenwasserstoffe" (Springer-Verlag) and in 1964 the greatly expanded two-volume Polycyclic Hydrocarbons, which described the syntheses, properties, and UV-visible absorption spectra of hundreds of PAHs. He discovered the Clar reaction of the cyclic ketone perinaphthenone to form dibenzo[cd,lm]perylene in a 400 C melt of zinc dust, zinc (II) chloride, and sodium chloride.  He created the Sextet Theory, now eponymously called Clars rule, to describe the behavior of polycyclic aromatic hydrocarbon isomers. This was described in his book The Aromatic Sextet'. He was awarded the August Kekulé Medal by the Chemical Society of the GDR in 1965, the highest award given by that society to foreign scientists, and the first Polycyclic Aromatic Hydrocarbon Research Award of the International Symposium on Polynuclear Aromatic Hydrocarbons in 1987. He died aged 84 in 1987 at Estepona.