Richard Matthew Stallman is a software developer and software freedom activist. In 1983 he announced the project to develop the GNU operating system, a Unix-like operating system meant to be entirely free software, and has been the project's leader ever since. With that announcement Stallman also launched the Free Software Movement. In October 1985 he started the Free Software Foundation.
The GNU/Linux system, which is a variant of GNU that also uses the kernel Linux developed by Linus Torvalds, are used in tens or hundreds of millions of computers, and are now preinstalled in computers available in retail stores. However, the distributors of these systems often disregard the ideas of freedom which make free software important.
That is why, since the mid-1990s, Stallman has spent most of his time in political advocacy for free software, and spreading the ethical ideas of the movement, as well as campaigning against both software patents and dangerous extension of copyright laws. Before that, Stallman developed a number of widely used software components of the GNU system, including the original Emacs, the GNU Compiler Collection, the GNU symbolic debugger (gdb), GNU Emacs, and various other programs for the GNU operating system.
Stallman pioneered the concept of copyleft, and is the main author of the GNU General Public License, the most widely used free software license.