Can anyone recommend books about isolated cults?

Edit: Sorry, should have specified fiction in the title

Think of isolated communities, off grid, earlier ages of technology. Almost like evil Amish. I've been thinking of writing a novella about a young woman that grows up in a cult, being able to see the rest of the world from behind a fence, but not knowing what it actually is. Are there any books which could help inform this or inspire me?

My current list is: The Handmaid's Tale, possible the Diary of Anne Frank

Thank you