The Moonstone is credited with being one of (if not the
) first detective mystery novels, and I wanted to read it because another book I plan to read references it.
I liked it. It is the proverbial English country house mystery. Nice little dead ends, twists and fun stuff. Unlikely (and likely) suspects, a little of the paranormal-ish... I think it was the first to really feature a twist at the end, but nowadays we're so used to twists, it wasn't one to me (seriously, it was easy to figure out, but fun).
The story is a little long. It takes place through several narrators, from the house-manager to the aristocratic guest, the lady's religious niece, the opium addicted doctor, and the retired, rose-growing detective.
There is not a lot of overlap in the narratives, and the narratives follow the story chronologically, making them a wee bit less tedious than if we had to read about the same event from 5 viewpoints. There's a lot of thought, introspection, distractions, and human frailties in the narratives that make them interesting.
I also think it has held up well over time. Not bad. I'd recommend it to anyone that likes to read these kinds of novels or even watch these kinds of movies/shows.