Richard Stallman (born March 16, 1953) is the founder of the free software movement, the GNU project, and the Free Software Foundation. He is also a famous hacker. He created GNU Emacs, the GNU C Compiler, and the GNU Debugger. He is one of the main authors of the GNU General Public License ("GNU GPL" or "GPL"), the most used free software license, which pioneered the concept of the copyleft.