This novel has been highly praised by SF fans and critics and has won most of the major awards for both SF and Fantasy in 2012. It's not hard to see why the it won the Nebula Award, Walton spends a good deal of the novel rattling off and commenting on both famous and obscure novels from the time period, and it's fun for the reader to compare notes with the writer, a critic's delight. The novel plays well with the concept of magic as well, avoiding the pitfalls of most Fantasy novels by placing the magic in a more modern setting and letting the reader question it's validity.
It's fun to read along with Walton as she name drops most major SF authors throughout the novel. I'm not sure how many common readers will recognize Delany or Zelazny, and I don't seem to love Tolkein as much as Walton does here, but it's really fun to watch her tick off these SF masters and compare opinions with her. My problem with this is that I don't see what it brings to the novel as a whole. Walton uses Mori's love of Science Fiction to underscore how much of an outcast she is among the girls at school and it serves well in that purpose. She uses these particular books because (it seems) these were the same books Walton was reading when she was the same age, but really any novels would have served the same purpose here, and not just SF authors.
What works better in the novel is the concept of magic, which Walton keeps relatively quiet and subdued. While anyone who bought this novel based on the synopsis on the back cover will come in expecting extraordinary magical battles between mother and daughter the book we actually receive is more about subverting expectations about the 'outsider at boarding school tale' and leaving the reader to question whether any description of magic in the book takes place in reality or all in the protagonist's head.
The novel can be read in two ways. Either this is the story of a young witch who escapes from her mother to an estranged father and ends up at a boarding school where she must constantly fend off attacks from her evil mother, or this is the story of an abused handicapped girl at boarding school who turns to SF and fantasy to escape the reality of her mentally ill mother and distant father. The beauty is that Walton is able to make these two stories equally compelling.
The question of whether the magic in the novel is really happening or not is unimportant. I know some people will hate the ambiguity, and normally I would be with them, but Walton has crafted such an impressive novel that either take on the matter will present a good story. If the magic in the novel is false then we are left to deal with the 'coming of age story' of a young girl who turns to SF for comfort from her depressing life and finds friends to help her cope, if the magic is real then we simply get all that plus a little magic on the side.
Walton has admitted that this is a mythological take on part of her own life. Apparently she walked with a cane as a teenager and attended the same school as Mori, she has also described the same sort of book club that Mori attends as having a large effect on her own life. I don't like to look too deeply into an author's life to reveal the meaning of a piece of fiction but when the author openly states that something is autobiographical you can't help but take a peek. I don't want to get into the game of finding out what in the book is based on the author's life and what is not (let's just assume the fairies are not) but maybe it does bring a little more realism and weight to the novel, and that's never a bad thing.
The part of the book I find most appealing is that it features a strong female lead, something not seen enough in SF today, yesterday, or ever. There are some pretty quick counter arguments to the notion that there are no female writers of SF (I usually just slap people in the face with LeGuin, who is number one on my list of Grandmasters), but it's not as if female writers must always write about female characters, LeGuin's most famous characters are all males plus one hermaphrodite. There are some strong, well developed female characters throughout the history of SF, but there are countless more damsels in distress, victims, and sex objects than I would care to mention. It's nice to see a writer out there willing to create a realistic female character, and as much as I hate to admit it, being based upon Walton herself might bring even more pathos to the character.
In the end most fans of SF will love this story for the Grandmaster name dropping alone, getting to count along with Walton as she ticks off all the great authors we've read (and maybe some we haven't) is a lot of fun and a nice salute to the fans as she acknowledges just who this book is for and who it isn't. While fun though, this might be the weakest point of the book as any esoteric hobby not easily accessible in the 70's could have taken the place of SF in the novel. The real strength of the novel lies in Mori's growth as a character and Walton's delightful depiction of magic in this world.
I think I've mentioned it before but Walton has her own blog where she goes back and talks about past Hugo Winners and Nominees here. It's a lot of fun and she definitely knows more about the Hugo's than I do. She reviews quite a few books there as well though she seems to skip out on reviewing most books she doesn't like (which is a shame as I really wanted to read her review of 'Ender's Game').