Richard Matthew Stallman is an American software freedom activist and computer programmer. He campaigns for the freedom of software endusers to use, study, share (copy) and modify software; software that authorizes these freedoms legally (via its license) is termed free software. Stallman opposes proprietary software which takes away a user’s rights to exercise these freedoms through restrictive software license agreements, non-disclosure agreements, activation keys, dongles, copy restriction, binary executables without source code and thus forces its users into a role of dependence on a company that seeks to control and monopolize the users and the market via these restrictions. In 1983 Stallman launched the GNU Project to create software of a Unix-like operating system, that will ensure it’s users will have the freedom to use, study, share and modify it. In October 1985 he founded the Free Software Foundation, and in 1989 he co-founded the League for Programming Freedom. Stallman is the main author of free software licenses which legally ensure that users have freedom to use, study, share and modify the software. The GNU software uses such licenses, e.g. the GNU General Public License (GPL), but these licences can be used by anyone, who wishes to ensure enduser’s rights to freedom of software use. The GPL is the most widely used free software license. Stallman pioneered the concept of copyleft that is used in some software licenses (such as the GPL), to ensure that free software (with its enduser freedoms) cannot become part of any proprietary software which would take these freedoms (use, study, share, modify) away again.