What effect does authorial intrusion yield in The Crucible?

Arthur Miller's "authorial intrusion" into the play's action provides background information on the characters and events that precede the spring of 1692 when the play begins. Miller's commentary enables readers to understand the beliefs and customs of the Puritans who populated Salem and its adjacent communities. Otherwise, modern readers might doubt that many people would believe that witchcraft and Satan's presence was a credible and constant threat to their lives. Moreover, because of Miller's commentary we understand that there are tensions among Salem's denizens and that politics are at work in their community. The church wants to maintain theocratic authority, but not everyone respects the local minister. For instance, some, like the Nurse family, would like to secede from Salem and create their own religious Utopia at Topsfield. The background Miller provides deepens readers' understanding of the characters and conflicts.