Charles Simonyi is a Hungarian-American software architect, businessman, and space tourist. He led the development of Microsoft's first application software, including early versions of Microsoft Office, and later co-founded Intentional Software, a company focused on his concept of intentional programming. A former researcher at Xerox PARC, he helped pioneer graphical user interfaces and introduced object-oriented programming and Hungarian notation to Microsoft. Simonyi flew to space twice as a private citizen, becoming the fifth space tourist and the only one to pay for two separate trips to the International Space Station. As of January 2025, his net worth was estimated at US$7.5 billion.

Charles Simonyi — Wikipedia