Raymond Duval is a philosopher and psychologist, devoted to researching mathematics education since the 1970s. He has worked at the Research Institute on Mathematical Education (IREM) in Strasbourg, France, from 1970 to 1995, where he developed an important research in cognitive psychology. Today, he is honorarius professor of the University du Litoral Côte d'Opale, France. His book Sémiosis et pensée humaine (1995) is a milestone in the theory of registers of semiotic representations, and his research papers over the years have greatly influenced research in mathematics education.