Benoît B. Mandelbrot (20 November 1924 – 14 October 2010) was a Franco-American mathematician. Born in Poland, he moved to France with his family when he was a child. Mandelbrot spent much of his life living and working in the United States, acquiring dual French and American citizenship.

Mandelbrot worked on a wide range of mathematical problems, including mathematical physics and quantitative finance, but is best known as the father of fractal geometry. He coined the term fractal and described the Mandelbrot set. Mandelbrot extensively popularized his work, writing books and giving lectures aimed at the general public.

Mandelbrot spent most of his career at IBM’s Thomas J. Watson Research Center, and was appointed as an IBM Fellow. He later became Sterling Professor of Mathematical Sciences at Yale University. Mandelbrot also held positions at the Pacific Northwest National Laboratory, Université Lille Nord de France, Institute for Advanced Study and Centre National de la Recherche Scientifique.