Since I read this to my 9YO, we skipped the author's essays. I like the idea of a themed collection, though trying to gather folktales around the theme of fear is, I think, tricky. All folktales have an element of fear, granted some more than others.
There were some good tales in here, and I liked the breadth of material. There were tales from native peoples of North America, Africa, Australia, various island nations to name a few, so it's a good collection to balance out the preponderance of European tales available in English.
Several stories were written in extremely heavy dialects, which just completely didn't work for me. Maybe because I was reading them aloud... It was just too much work to try to parse the meaning of each sentence to get through the story. We ended up skipping those stories.