Julius J. Epstein, Philip G. Epstein & Howard Koch

The screenplay of Casablanca carries three credited writers — twin brothers Julius J. Epstein and Philip G. Epstein, who shaped the structure and the film’s celebrated wisecracks, and Howard Koch, who handled the politics. They were adapting an unproduced 1940 stage play, Everybody Comes to Rick’s, by Murray Burnett and Joan Alison. Because the credit is genuinely shared and the picture was rewritten during shooting, no single one of the three can be named as the author of this particular line — and the character Ilsa and the actress Ingrid Bergman are not its authors at all.