Published by Wilkie Collins in 1968, The Moonstone is considered to be the first mystery/detective novel written in England. It has relatively enlightened views about society, for example about how servants are treated.
The Moonstone is literally a huge diamond stolen from a Hindu temple in India. It was given to the niece of the guy who stole it only to be stolen. There are so many red herrings. So many of the characters are suspicious and have to prove their innocence.
Of course, there is a final twist and the mystery is solved.
The Moonstone was exciting and interesting and much more complex than is often experienced in many modern novels. I really enjoyed the novel.
You can get it for free online, just so you know.