Joseph Campbell studied myths from cultures all around the world and found a number of recurring incidents featured in these stories despite the fact these cultures were separated by time and distance and were impossible for them to have come in contact with each other. He concluded that these recurring incidents were part of human psyche. He outlined this in his book Hero with a thousand faces. To really understand this theory you need to read his book.
These pages are presented as a guide to give a brief overview of the stages and to assist in creatively interpreting the stages for your own writing. Although Ordinary World is not a part of the Hero’s Journey, it’s part of Christopher Vogler’s Writer’s journey, it’s commonly used in film and so is included here.