This book is a historical fiction grail thriller/mystery following in the wake of such works as The Da Vinci Code, and though Mosse is definately a fine weaver of stories the overall skill of the writing produced here is not great, as with its forerunner mentioned above.
I found the work at times to jar with the flow of reading when I had to question not only Mosse's vocabulary choice, but the validity of the actions represented. As it is a huge work, nearly 700 pages in total, there are bound to be mistakes where the editting has failed, but I would expect more from a writer than to contradict themselves mere paragraphs apart. Mosse also represents herself as a somewhat lacking scribe, as the quality of her language use is often lower than it could be. I found myself questioning her grammar frequently and her overuse of words and phrases more often. I don't claim to be perfect myself, but this is the kind of thing which can interrupt a good reading of a novel. The way the author started and ended using the present tense to write also didn't sit with me well, and I'm glad that this was disregarded for the work as a whole.
Nonetheless, Labyrinth is a decent historical fiction/mystery read (and a much better grail thriller than The Da Vinci Code). The story itself is interesting and involving for the reader, as any mystery should be, though I found myself less interested in the present-day Alice story than her historical counterpart. Not a bad read, but not something I would seek out again, and I probably won't continue to read her writing unless I hear her writing style has improved.