Joseph Campbell was a Professor of Literature, philosopher, and writer whose study of world mythologies influenced cultural producers from movies to literature.
The Star Wars films created and produced by George Lucas followed the structure of Campbell's monomyth. The following is a summary of the Hero's Journey in infographic format. The ideal way to know more about the monomyth is to read the work of Joseph Campbell in the books: The hero of thousand faces and The power of myth.
Joseph Campbell (wikipedia)