The mathematician credited for laying the groundwork for modern computer programming languages, Kristen Nygaard, has died at age 75 in Oslo, Norway. Nygaard and his colleague designed Simula, a programming language created to simulate real world systems, in the mid 1960s. Simula pioneered the concept of object based programs, or classes of objects and modules, which strongly influenced the design of computer languages, such as Smalltalk, C++, and Java. Nygaard’s research and Simula greatly influenced other computer scientists in the 1970s, including those at Xerox Corporation’s Palo Alto Research Center. Work at the Palo Alto Research Center ultimately influenced computer designers in the 1980s at Apple and Microsoft, which led to the development of Windows and Macintosh operating systems. Nygaard also pioneered the concept of `participatory design,’ where workers cooperatively design products and technology within their work environment.