I'm really glad I picked this book up. Technically a YA book, there was nothing in it that screamed "Young Adult" to me. The plot was gripping, the world(s) fully defined, the main character richly developed and likeable, and (and this is important to me) the secondary characters also incredibly well-defined, full and interesting. I also absolutely loved how the author describes the settings of the book. There are many locations, but the bulk of the novel takes place in Prague. The way the author describes this city -- it's just breathtaking, and it made me feel like I was THERE.
I knew very little about this book when I picked it up, and so I literally had no clue where this was going when I started it. But I was completely drawn in by the story. I don't want to give away anything, so I won't get into the plot at all -- just that it felt wholly original and fresh to me, and that I was surprised again and again.