For several years, every November (with the exception of while I was in college), I re-read the Sherlock Holmes canon. If there was ever a series that could fill the yearning I always feel for more of the same kind of Victorian mystery and pure friendship, this is that series.
Barker and Llewelyn are a great pair, a study in contrasts given Barker's slightly misanthropic, wizened and dourly religious discipline and Llewelyn's youthful impetuousness and gregarious, if a tad naïve at times, nature.
Will Thomas borrow liberally from history, and his Victorian London teems with wonderful characters both real and not. Unlike many Victorian mystery series, the melting pot nature of the city is never neglected. In addition to Barker's Oriental roots, adding an interesting perspective on Victorian London, the narration sweeps you into a bustling world on both sides of the track in every book.
The supporting characters, such as Mac, the butler, or the French chef Etienne, are all as interesting as the protagonists. You spend much of the book looking forward to bumping into the minor characters as much as you do to following the always-clever plot twists.
If Holmes and Watson are to ever have competition in the hearts of mystery lovers, Barker and Llewellyn are sure to be front runners in giving it.