Critics of the 2015 film Star Wars: Episode VII – The Force Awakens have called the film unoriginal and predictable because the story so closely mirrors the very first Star Wars film in 1977. But, in fact, both films follow a structure that pre-dates all Hollywood films, that of the 'hero myth'. That's because director George Lucas based Star Wars on the ideas in Joseph Campbell's 1949 book, The Hero with a Thousand Faces. Later editions of Campbell's book even featured Star Wars' hero Luke Skywalker on the front cover. In his book, Campbell analyses myths from all over the world to describe the 'monomyth' – a pattern that you can see in myths from every culture. In short, a hero sets off from home on a journey, where he overcomes obstacles and defeats enemies to return with a prize. It's a tale that has been told for thousands of years, from the Ancient Greeks with The Odyssey to JK Rowling's Harry Potter books. George Lucas was one of the early film directors to directly base his story on the 17 stages of the hero's journey. Typically the hero starts the story living an ordinary life, but something happens that calls them to an adventure that changes everything. At the beginning of Star Wars, Luke lives an ordinary life with his aunt and uncle, repairing robots. When he finds Princess Leia's message to Obi-Wan Kenobi inside the robot R2D2, it is 'the call to adventure'