I'm verging in 4.5-5 territory here. I've had this one on my list for a long time, always intrigued by the story (magical worlds torn apart by power yet connected by individuals who can walk between them with relative ease) but I always had something else in my TBR - plus, this felt like a good "intro to spooky season" read (magic, et al), so I waited. But thank god the wait is over. Schwab writes effortlessly in a way that makes a 400 page book fly by in such a satisfying way. The characters, too, are so naturally drawn: you know exactly who they are by their actions and interactions, without leaning on caricature or easy tropes. The world building is perfect, as well, with just enough elements of reality to ground the magical world that has its own logical rules that don't demand a lot of exposition or explanation. Yet magic in this world is also unique, demanding attention and requiring sacrifice, a fact that is evident from beginning to end. There are serious stakes for all characters, and the ending is satisfying but open-ended enough to leave me excited to step back into this world for book two - something that admittedly doesn't happen that often for me. Maybe my only qualm is that I wanted more of this shaded reality beyond London. Guess I'll just have to keep reading to find out if the borders broaden and take our characters beyond the Thames.