John Horton Conway (26 December 1937 – 11 April 2020) was an English mathematician. He was active in the theory of knot theory, number theory, and coding theory. He also made contributions to many branches of recreational mathematics, most notably the invention of the cellular automaton called the Game of Life.

Conway invented the Game of Life, one of the early examples of a cellular automaton. His initial experiments in that field were done with pen and paper, long before personal computers existed. Since Conway's game was popularized by Martin Gardner in Scientific American in 1970, it has spawned hundreds of computer programs, web sites, and articles. The game helped to launch a new branch of mathematics, the field of cellular automata. The Game of Life is known to be Turing complete.

Conway based the Game of Life on cellular automata, a mathematical model created by John von Neumann in the 1940s. A cellular automaton consists of components called “cells” that form a one or multidimensional lattice. In the Game of Life the lattice is the checkerboard. He is the mid point between the algorithmic pioneers and artificial life artists.