About a succinct summary of the history and art of film composing as you’ll find.
Steiner composed 11 other film scores the same year he worked on Gone with the Wind.
James Horner said of his work for Titanic: “I probably wrote all the material in about three hours. The themes literally came to me in 20 minutes.”
On the other hand, John Williams went through 300 versions of the five-note alien greeting from Close Encounters of the Third King before Spielberg was happy.
Those five tones from Close Encounters are embedded in the score, they are heard in the lead-up to the communications sequence. Back up this video a bit to hear them. (By the way, isn’t it lucky the aliens happened to have a tuba player aboard?):