One of my favorite, favorite, favorite things about this series is the way that Laurie King weaves in literary references. The Hounds of the Baskervilles and Reverend Sabine Baring-Gould in The Moor. Rudyard Kipling's Kim in The Game.
And now, Dashiell Hammett in Locked Rooms. Yes, that Dashiell Hammet.
I am constantly awestruck by the depth and quality of Laurie King's historical research. This is how writing about history should be done - with careful precision and obvious delight in the process.
Every one of these books is different, but the constant thread of characterization and history is amazing.