The document discusses operating systems and their evolution. It describes how early operating systems like MS-DOS used command line interfaces rather than graphical user interfaces. It then explains that Apple developed one of the first GUIs which was used in the Apple Lisa and later the successful Macintosh in 1984. Microsoft then entered the market with Windows 1 in 1985, but it was not until Windows 3.0 in 1991 that Windows became a successful operating system that provided a GUI alternative to DOS.