The Saint of Bright Doors

I picked this one up as the most recent winner of the Nebula award. It’s a fantasy novel, where a boy has his shadow severed from his body by his mother, and then he grows up to move to a city where there are inexplicably glowing doors all over the place that don’t lead anywhere. The book itself was easy to read, and some of the characters felt easy to connect with, but overall the plot felt quite vague at times. From reading the reviews afterwards it seems the wow factor comes from the themes it covers - religious fanaticism, totalitarianism and so on but I think it was a bit lost on me and I would have liked something more tangible.