Stephen Wolfram is a British scientist and the chief designer of the Mathematica software application and the Wolfram Alpha computational knowledge engine. 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. In March 2009, Wolfram announced Wolfram|Alpha, an answer engine with a new approach to knowledge extraction and an easy-to-use interface, launched on May 16, 2009 and a Pro version launched on February 8, 2012 The engine is based on natural language processing, a large library of algorithms and answers queries using the approach described in A New Kind of Science. The application programming interface (API) allows other applications to extend and enhance Alpha. Wolfram|Alpha is one of the answer engines behind Microsoft's Bing and Apple's Siri (along with Google and Yelp!) answering factual questions.