I've been a Sherlock Holmes fan since I was a kid, and have been an enthusiast, not only for the fiction of Conan Doyle, but for the variations on the character that have almost obscured the "real Holmes." Of the film treatments, I always appreciated Jeremy Brett's "orthodoxy," and I think I liked "The Seven Per Cent Solution" more for its swashbuckling Sigmund Freud that for its Holmes. I thought George C. Scott was awfully good in "They Might be Giants" (I assume, until corrected, that Joann Woodward's Mildred was the first female Dr. Watson). I have very much enjoyed Benedict Cumberbatch's "high functioning sociopath," though his characterization owes a little too much to the revived Doctor Who.
Still, it's fun to go back to Doyle, as I recently did in completing The Valley of Fear.
The Holmes novels have always been less prized that the stories--with the exception of The Hound of the Baskervilles. That's probably because, unlike The Hound, they spend a lot of time away from Holmes. In The Valley of Fear the first half of the novel covers the murder, Holmes' investigation, and the solution, a satisfactory if (by cinematic standards) low-key resolution involving a missing dumbbell, a hidden bicycle, and the taking of a single, inner ring from a finger of the victim. There's even a bit of Professor Moriarty, mostly as window dressing.
The second half of the novel is an entirely different story, explaining the background and motivation of the killing. It's set in America, and it's just "wrong" enough to give the story an interest entirely separate from the plot.
I once had a friend who returned from a trip to England with a trove of English comics. One dealt with the adventures of a certain "Dead-Eye Dick," the cover of which afforded us endless amusement. It portrayed a saloon, someplace in the Rockies, I think. A gunfighter has burst in through the swinging half-doors, and our cowpoke hero has risen from his poker game, fire in his eyes, and exclaims, "Whatever do you mean by this intrusion??"
The second part of the book is set in a rough American mining community, terrorized by an organization call the "Scowrers." Doyle apparently didn't make up the scenario out of whole cloth; he based it on a book he read extolling the Pinkerton private detective organization, and a Pinkerton is, in fact, the eventual hero of the tale. The Scowrers are members of what is equal parts fraternal organization, labor union, and Murder, Inc. Whether anything like this in fact existed I'm not able to say. The enemy seems always to be articulated as "capitalists," but murders are committed by request, no questions asked, ruthlessly and frequently, often of wholly innocent workers. Hence, The Valley of Fear.
As a stand-alone novel I would guess that it has Holmes alone to thank for it's still being printed. And as a picture of American life and labor relations, it seems to fall into the seriously "wrong" category. But as a period Edwardian melodrama and a window into the way that Englishmen of that period saw America, it has its interest.