Richard Stallman is a computer programmer and software freedom activist. In 1983 he announced a project to develop the GNU operating system, which is meant to be entirely free software, and he continues to be the project's leader. In 1985, he launched the Free Software Foundation, and in 1989 he co-founded the League for Programming Freedom. The GNU/Linux system is now used in tens or hundreds of millions of computers. Since the mid-1990s, Stallman has been an advocate for free software, and has campaigned against software patents and extensions of copyright law. He pioneered the concept of "copyleft" and is the main author of the GNU Public License, the most widely-used free software license.
Stallman contributed the dangerous idea that all software should be free to Big Think's "Month of Thinking Dangerously."