Ben Aaronovitch "The Masquerades of Spring"

I just got my copy of the latest Rivers of London
novella.  This one isn't, strictly speaking, a
Rivers of London.  The book steps well back in
time into the 1920s.  Nightingale travels to
New York City to trace the source of a magic
saxophone. Here he meets the world of Harlem
and Jazz.  He doesn't meet any of the river gods
of New York. I don't think that the book is quite
up to the standard of Aaronovitch's earlier works,
but it is a fairly good read in any case.
Note:  My copy of the book is a collectable.  It
is signed and numbered.  I didn't realize that
until I got it.
Bill