I had a few thoughts about what to read for this square.
I considered re-reading Neverwhere by Neil Gaiman; lets face it, you can never have too much Gaiman.
And another choice was The Severed Streets by Paul Cornell. It's the second in his Shadow Police series about a London police force investigating supernatural happenings.
But I've been meaning to read the Rivers of London books for a long time now. I'm 3% in and I'm pretty certain I'm going to enjoy the ride.