Stephen Wolfram (born 29 August 1959 in London) is a British physicist, software developer, mathematician, computer programmer, author and businessman, known for his work in theoretical particle physics, cosmology, cellular automata, complexity theory, computer algebra and the Wolfram Alpha computational knowledge engine. Stephen Wolfram’s parents were Jewish refugees who emigrated from Westphalia to England in 1933. Wolfram’s father, Hugo Wolfram, was a novelist (Into a Neutral Country), and his mother, Sybil Wolfram, was a professor of philosophy at the University of Oxford. He has a younger brother, Conrad Wolfram. Wolfram was educated at Eton. At the age of 15, he published an article on particle physics and entered Oxford University (St John’s College) at age 17. He wrote a widely cited paper on heavy quark production at age 18. Wolfram received his Ph.D. in particle physics from the California Institute of Technology at age 20 and joined the faculty there. He became highly interested in cellular automata at age 21.

Wolfram’s work in particle physics, cosmology and computer science earned him one of the first MacArthur awards. His work with Geoffrey Fox on the theory of the strong interaction is still used today in experimental particle physics. Wolfram founded the journal Complex Systems in 1987. Wolfram led the development of the computer algebra system SMP (Symbolic Manipulation Program: SMP was essentially Version Zero of Mathematica) in the Caltech physics department during 1979–1981, but a dispute with the administration over the intellectual property rights regarding SMP—patents, copyright, and faculty involvement in commercial ventures—eventually caused him to resign from Caltech. SMP was further developed and marketed commercially by Inference Corp. of Los Angeles during 1983–1988.

In 1981, Wolfram was awarded a MacArthur Fellowship. In 1983, he left for the School of Natural Sciences of the Institute for Advanced Study, where he studied cellular automata, mainly with computer simulations. In the middle 1980s Wolfram worked on simulations of physical processes (such as turbulent fluid flow) with cellular automata on the Connection Machine alongside Richard Feynman. In 1986 Wolfram left the Institute for Advanced Study for the University of Illinois at Urbana-Champaign where he founded their Center for Complex Systems Research and started to develop the computer algebra system Mathematica, which was first released in 1988, when he left academia. In 1987 he co-founded a company called Wolfram Research which continues to develop and market the program.