Computers: "In The Beginning," How Many GUIs Were There?

A review:

So, rather than a single number, the "beginning" involved a competitive landscape with several companies developing and releasing their own distinct graphical interfaces. 

Look at the time frame: 

• baby footsteps: 1973
• ten years later, 1883: the first commercial personal computer - Apple Lisa GUI
• another two years, 1985: Microsoft Windows 1.0