January 1973: George Lucas begins writing the first of four drafts of the Star Wars screenplay. May 1973: Lucas completes 13-page plot summary that opens with the line: "This is the story of Mace Windu, a revered Jedi-bendu of Opuchi who was related to Usby C.J. Thape, padawan learner to the famed Jedi." May 1974: Lucas finishes writing The Star Wars - this rough draft being the first of the four screenplay drafts for Star Wars. January 28, 1975: Second draft of Star Wars is completed - The Adventures Of The Starkiller, Episode 1: The Star Wars. August 1975: Third draft of the screenplay is finished - The Star Wars - from The Adventures of Luke Starkiller. January 15, 1976: The revised Fourth Draft of the screenplay is completed - Star Wars, Episode IV: A New Hope from The Journal Of The Whills by George Lucas. Back in the 70's, Lucas had no idea how everything would turn out, he didn't even know that he would be able to do a "second" STAR WARS film. All he had was a (constantly changing) story that was way too long - so he decided to skip the part that dealt with the rise of the Empire and where Darth Vader and Kenobi came from and start in the middle of the story instead. (Many of literature's great works begin "in medias res".) After the success of STAR WARS, Lucas decided to do two sequels, and to give the plot momentum, he turned Vader into Luke's father, making it necessary for Kenobi in JEDI to explain the things he'd said about Luke's father in the original STAR WARS. Then, in 1994, Lucas started writing the prequels. The main plot elements had been conceived in the 70's and 80's (Kenobi, Vader, Palpatine, Luke, Leia, their mother) but I doubt that there was a "story" or "Gungans" or anything as concrete as that when Lucas sat down in 1994. I think the prologue of the STAR WARS novel (by Alan Dean Foster) is interesting as it gives you insight into the back story of STAR WARS that existed in 1977. To Lucas credit, he stuck closely to his initial vision when he developed the prequels so much later in life. Another galaxy, another time. The Old Republic was the Republic of legend, greater than distance or time. No need to note where it was or whence it came, only to know that ... it was the Republic. Once, under the wise rule of the Senate and the protection of the Jedi Knights, the Republic throve and grew. But as often happens, when wealth and power pass beyond the admirable and attain the awesome, then appear those evil ones who have greed to match. So it was with the Republic at its height. Like the greatest of trees, able to withstand any external attack, the Republic rotted from within though the danger was not visible from the outside. Aided and abetted by restless, power-hungry individuals within the government, and the massive organs of commerce, the ambitious Senator Palpatine caused himself to be elected President of the Republic. He promised to reunite the disaffected among the people and to restore the remembered glory of the Republic. Once secure in office he declared himself Emperor, shutting himself away from the populace. Soon he was controlled by the very assistants and boot-lickers he had appointed to high office, and the cries of the people for justice did not reach his ears. Having exterminated through treachery and deception the Jedi Knights, guardians of justice in the galaxy, the Imperial governors and bureaucrats prepared to institute a reign of terror among the disheartened worlds of the galaxy. Many used the imperial forces and the name of the increasingly isolated Emperor to further their own personal ambitions. But a small number of systems rebelled at these new outrages. Declaring themselves opposed to the New Order they began the great battle to restore the Old Republic. From the beginning they were vastly outnumbered by the systems held in thrall by the Emperor. In those first dark days it seemed certain the bright flame of resistance would be extinguished before it could cast the light of new truth across a galaxy of oppressed and beaten peoples ... From the First Saga Journal of the Whills by George Lucas