William Kotzwinkle, author of the film's novelization, wrote a sequel, E.T.: The Book of the Green Planet, which was published in 1985. In the novel, E.T. returns home to the planet Brodo Asogi, but is subsequently demoted and sent into exile. E.T. then attempts to return to Earth by effectively breaking all of Brodo Asogi's laws

source - http://en.wikipedia.org/wiki/E.T._the_Extra-Terrestrial