American Graffiti is a coming of age film made by George Lucas after he had a bet with friend and mentor, Francis Ford Coppola. The film was released on August 11th, 1973 and was based on George Lucas's life as a teenager growing up in Modesto, California in the early 60's.
The film stars Ron Howard, Richard Dreyfuss, Paul Le Mat, Cindy Williams, Charles Martin Smith, Wolfman Jack and Harrison Ford in a cameo. The main characters are all friends who live in Modesto, as the film details their lives during an entire night, as they party, have fights, and cruise in their cars, the way life was for young folks back in the 60's.
It's curious to note that three of the main characters in the film where all based on George Lucas at different points throughout his early teenager/young adult life. George may not have been the most popular kid back in the day, but he later went off to become a hell of a car racer. His passion was at one point so big that he wanted to go into car racing professionally, but a terrible accident at some point in his life ended his dream. Some of that passion must have lived with him, since in all of his films, some type of race occurs, be it a normal car race, a Podrace or a Trench Run. It's even known that Lucas went recently to a Formula 1 race in Monaco.
The importance of American Graffiti, looking back on it in retrospect, is to show that whoever you were in High School: be the popular kid, the normal boy, or the underdog, won't determine your success later in life. If you need anymore evidence, simply look at the maker himself. This theme is also evident in the Star Wars films, as both Luke and Anakin came from humble origins, and were underdog's that became heroes once they embarked in an adventure.
I personally think that the film is a fun one to watch, that also has a message of ''simplicity'': Life was better in the old days, when it revolved around small towns and everyone knew each other, and when young folks would listen to rock and roll and cruise in their cars because their was nothing better to do. Nowadays the world is a much more complex place, where popular culture has enforced a ''mono-culture'' in film, music and other media that seeks to get young people to identify with vice, misogyny and materialism over their traditional values.
George Lucas had proven to the world that he could make a successful film that the public would love. He had the vision and the capacity to make Star Wars. The rest, you could say, is history.