Come Monday I get to do some proper policing. Person Unknown has been stabbed to death on the tracks at Baker Street tube. Magic may have been involved. And sure enough, in the blood; vestigia, the tell-tale trail magic leaves. Person Unknown turns out to be the son of a US senator and before you can say 'International incident', FBI agent Kimberley Reynolds and her firmly held religious beliefs are on my case. And down in the dark, in the tunnels of London's Underground, the buried rivers, the Victorian sewers, I'm hearing whispers of ancient arts and tortured, vengeful spirits . . . Praise for Ben Aaronovitch's DC Peter Grant novels 'Fresh and original and a wonderful read. I loved