I first learned about Gail Carson Levine's Princess Tales from a friend while discussing another of Ms. Levine's books, Ella Enchanted. Although Ella Enchanted, Ms. Levine's first book, is certainly more well known it is not her only fairytale story. In the last ten years Ms. Levine has written over fifteen additional books, including the aforementioned Princess Tales, which are more novellas than novels. Written with children ages 4-9 in mind, the books are very short and simply told. Depending on the publication the books run between 87 and 96 pages.
The Fairy's Mistake is the first in the series and is a tale of twin sisters, Rosella and Myrtle and their widow mother in the magical kingdom of Biddle. The title of the book refers to what occurs when a fairy casts a spell upon each of the sisters -- one who is kind and the other who is unkind. I read that Levine adapted her story from an ancient French fairytale called "Toads and Diamonds" by Charles Perrault.
Overall I found the story clever, though not exactly my type of fairytale. What do I mean by that? Well, because one of the spells had some rather... um... creepy-crawly results I was glad I was reading the story and not watching it! It did remind me a little of what the Brother's Grimm might write if they were alive today and still adapting folk lore into fairytales. I am not a huge fan of the Brother's Grimm, but there is the occasional gem that I enjoyed.
Even so, I did enjoy the book and it was very fast reading -- completed in about a half-hour. I'd like to read the rest in the series to see what they are like. I know at least one is the retelling of The Princess and the Pea. Also, I want to read Ella Enchanted. I enjoyed the movie and the story appears to be an original tale by Ms. Levine.
In a nutshell: fans of unusual fairytales and fans of the Brother's Grimm will enjoy these fairy tale novellas. Depending on the reader it might even be a fun read aloud to children. I'd advise borrowing rather than buying -- at least until you know whether or not you love these books and want to add them to your personal library.