Harry Kesten (November 19, 1931 – March 29, 2019) was an American mathematician. He best known for his work in probability, most notably on random walks on groups and graphs, random matrices, branching processes and percolation theory. He wrote 191 papers and has been cited by more than 2,300 researchers. He has been called of the most inventive and important experts of probability theory. He worked at Princeton University, the Hebrew University of Jerusalem and Cornell University. He was born in Duisburg, Germany and grew up in the Netherlands.