President of Wolfram Research and creator of Mathematica, a symbolic mathematics package that also does numerical calculations. Wolfram was born in London in 1959, and went to Eton, Oxford, and Caltech. By all accounts, he was a prodigy: he published his first paper at age 15 and got his PhD by age 20. Wolfram's career took him from physics into early work on Cellular Automata.

He comes across as brilliant but also as a shameless self promoter and grating egotist, when compared to quieter and more productive contemporaries such as Cleve Moler. For example, from the very first line of the book he wrote, "The Mathematica Book":
Stephen Wolfram is the creator of Mathematica and is widely regarded as the most important innovator in scientific and technical computing today.
(Wolfram wrote this note about himself despite the fact that at the time he had not published anything new since the mid 1980s.)