Harry Kesten (1931-2019), a personal and scientific tribute.

The mathematical achievements of Harry Kesten since the mid-1950s have revolutionized probability theory as a subject in its own right and in its associations with aspects of algebra, analysis, geometry, and statistical physics. Through his personality and scientific ability, he has framed the modern subject to a degree exceeded by no other. The impact of his work and personality is summarised in this memoir.