The Free Software Foundation (FSF) was founded in 1983 along with its demonstration GNU project. Richard Stallman, an MIT professor, had worked as a student on projects where software was freely exchanged without copying or modifying stipulations. Why, he asked himself and others, should software users be prohibited from copying it for friends, looking at the source code and copying it, and redistributing the results? Taking this idea to the group level, Stallman and others created the FSF and set out to demonstrate that an entire operating system could be developed and shared freely. The result was the Unix-like GNU, which, in August 1996, became complete by adding a kernel.
The "free" does not mean at no charge. The Free Software Foundation does charge an initial distribution price for GNU. "Free" refers to the use the person who acquires the software has with it. The Free Software Foundation believes that individuals and society would benefit from, and moreover have the right to study a program's source code to discover how it works, to make changes that enhance the program in some way, and to redistribute and even to sell improved versions to others as long as they in turn make their software free of reuse restrictions.