Once Upon a Curse is an anthology of fairy tales that focus more on the evil aspects of stories than the good. Most stories still have their happily ever after, but there's always some sort of twist.
I enjoyed each of the stories in this collection. They were all an interesting spin on old stories. If I had to choose a favorite, though, I'd have to go with the last story, "But Can You Let Him Go". It was based on Cinderella - not just the commonly used French version, but several different cultures' versions of the tale. The story was very well done - I loved how the story sort of spiralled in on itself, until only the ending remained.
The first story was a close second for me, but I've always enjoyed Bluebeard.
I don't so much see that this book was for "adult readers". Teen/young adults would probably be a better audience. It definitely isn't a kid's book. But it definitely has a wider appeal than just adults.
This is a good book to read if you enjoy reading fairy tales with a twist, or just retellings of fairy tales in general.