Seymour Ivan Rubinstein (born 1934) is an American businessman and software developer. With the founding of MicroPro International in 1978, he became a pioneer of personal computer software, publishing under it the extremely popular word processing package, WordStar. He grew up in Brooklyn, New York, and after a six-year stint in New Hampshire, later moved to California. Programs developed partially or entirely under his direction include WordStar, HelpDesk, Quattro Pro, and WebSleuth, among others. WordStar was the first truly successful program for the personal computer in a commercial sense and gave reasonably priced access to word processing for the general population for the first time.