How do you MLA cite an annotated book?

I am writing about Grimms' fairy tales for a research paper. I have the collection of their stories in a book, and it is annotated and edited by Maria Tatar. In my paper I am going to use both information from the fairy tales themselves and from Tatar's annotations and introductions to the stories. Do I make two separate MLA citations for when I'm using Tatar's annotations vs. brothers' fairy tales? Or just one? I'm not sure what to do here....