Sarah Monette's _Melusine_ is a fabulous debut fantasy novel, about a pair of unlikely heroes in a richly imagined world. Felix Harrowgate is a wizard of the Mirador, powerful and respected until a long-held secret is divulged which drives him back to his evil master, Malkar, and into insanity. Meanwhile, the thief Mildmay the Fox is drawn into intrigue when he meets Ginevra, a beautiful shopgirl who wants him to steal back some items from her former lover. Eventually, the separate stories of Felix and Mildmay combine into one, as they form an unlikely partnership.
The real triumph of _Melusine_ is in its language and voice. Monette tells the story in three separate voices -- Felix's haughty sanity, Felix's insane delirium, and Mildmay's slangy thieves' cant -- and she handles them brilliantly, never losing her grasp for an instant or letting the reader be confused about who's narrating. Along with the narrative voices, the language is simply lush and vivid, utterly suitable to the richness of the setting; the city of Melusine is particularly well described in Mildmay's sections of the narrative.
As far as the characters go, I preferred Mildmay's narrative to some extent, as he's the more immediately sympathetic character, with unsuspected depths of feeling. Felix falls into madness so quickly that it was a little difficult for me truly to enpathize with the change in his circumstances, as there had been so little time to get to know him before his fall. Still, the vivid, present-tense passages where he's delirious and mad are emotionally compelling, simply for the horror of what he endures.
I should say here that I think the publishers of _Melusine_ did the book a terrible disservice by failing to mention anywhere in the book (even on the last page) that it is the first of two books; there is an upcoming sequel, due out next summer, currently titled _The Virtu_. If I hadn't known before I started _Melusine_ that there would be another book, I would have been very disappointed in the lack of any real resolution to the plot. As it is, I was able to revel in the rich setting, languages, and characters, and now I can look forward to rereading _Melusine_ when _The Virtu_ is published.