The song "Love Story" was written by the American singer-songwriter Taylor Swift. She wrote it inspired by a boy who was unpopular with her family and friends, using Shakespeare's Romeo and Juliet as a reference point, but with a happy ending of a marriage proposal.

The novel and film "Love Story" from 1970 were written by Erich Segal. He wrote the screenplay and then novelized the story just prior to the movie's release. The story became widely popular as a romantic drama.

The theme music for the 1970 film "Love Story" was composed by Francis Lai.

So, depending on the context:

• The pop song "Love Story" is by Taylor Swift.
• The novel and film "Love Story" are by Erich Segal.