The Masquerades of Spring, by Ben Aaronovitch

The latest Rivers of London novella goes back in time to see chief London wizard Thomas Nightingale visiting New York in the 1920s to track down magically malign instruments. Seen from the point of view of expat colleague Augustus Berrycloth-Young, this entertaining tale sheds light on the earlier days of Nightingale, although Gussy’s voice gets a bit twee. While the back story short stories and novellas are fun, it must surely be time for a proper novel that takes the saga forward.