Ariel is a short novel by Grace Tiffany, published in 2005 The novel is a retelling of William Shakespear's play The Tempest. Grace Tiffany is an academic Shakespeare scholar that has also written two popular books about Shakespeare and his works. The novel is nominally for the young adult market, but the subject matter and sophistication are quite adult.
The book is called Ariel because it centers on this spirit, who was only a supporting character in the original play. The book describes how she meets the other characters in the play and manipulates them into a conflict that is not quite the one described in the play. All of this is formed because, as the first sentence of the book states:

The first thing you should know about Ariel is that she's a liar.
Ariel is not a malicious liar, so much as that she does not know the difference between stories and reality. She is formed from the dying thoughts of an early church apostle, blown off course and eventually staggering onto a Caribbean beach. All of the dreams in his head turn into this new entity, Ariel. Over the next few hundred years, she lives a life of fancy until she meets the next occupants of the island: Sycorax, the English slave of viking raiders who is pregnant with a child. Ariel, a creature of fancy, doesn't understand the nature of pregnancy, or the suffering that goes along with it, and is unable to help Sycorax in her difficult labor. Later on, Ariel manipulates Caliban into killing his mother, an act he suddenly regrets. When Prospero and Miranda arrive, Ariel uses her powers of illusion to set Prospero against Caliban. When the rest of Prospero's family arrives, Ariel creates more struggle and conflict with them. In the book, it turns out that neither Prospero nor his brother were ever dukes: they were just successful farmers. Eventually, the illusions are seen through, and people leave the island, with some of the relationships different than in the play. The plot of the book is only sketched out here, for a full explanation, the book and the original play should be read.

There are several things that make this book interesting. The first is the obvious retelling of the story away from some of the colonialism of the original. Caliban is not a savage, nor does he assault Miranda. Instead, he is merely cast in that role by Ariel, for the sake of causing problems. Instead, Caliban is Miranda's best and only friend, and ends up romantically involved with her, despite Ariel's attempt to make Miranda love the weak, ineffectual Ferdinand. Apart from just colonialism, the book messes with the entire dramatic convention of things reaching a neat and tidy ending. That dramas follow predictable patterns is only believed by Ariel, who does not understand how human events really happen. This for me, is the real thrust of the novel: whether having dreams, even fulfilled dreams, is ever as good as having realities. There is several ways to parse this. One that occurred to me after realizing that this was a young adult book is that Ariel is the prototypical teenage girl who lives for drama, conflict and rivalry, even when she doesn't really know what it means. In that way, the message may be more immediately obvious to its intended audience than it was to me. Another possible interpretation is that Grace Tiffany is taking the reference to Ariel in a meaning more original than Shakespeare took it: as a reference to the gnostic angel of illusion and deception, Ariel. Given the first sentence of the book, it seems like a likely enough interpretation.

Of course, none of these interpretations should be taken as the point of the book. As is the case with the play of Shakespeare himself, people often forget that these things are just wonderful stories.