This is the fourth book I have dedicated to you, and you will see why if
you read it--which no one need do.
First, emeralds are green; and, on principle, like the Green Overcoat,
it owes to you of the Green Elephant, a dedication. Next, there is
Catherine the Great. She plays no long part, but she founded the
fortunes of them all; and we are in communion in the matter of that
large and generous but regal soul; we agree that it is a pity she died
before we were born. Also, you who know all about Russia, and I who know
nothing, have, in the matter of Russia, this Monarch of all the Russias
for a link.
Lastly, you have often urged me to write a detective story, because (you
assured me) they have gigantic sales. I promised you I would, on
condition there was nothing to find out.
Here it is.