What's In A Mystery?

I read a book called "The Mystery Tomb" recently. Can you guess, it was a mystery? Characters had mysterious backstories. Locations revealed unexpected treasures. Desire and intention collided while truth slipped and slid, awaiting the final reveal. Mystery for sure. "Deadly Spirits" is a mystery driven by a wonderfully human narrator whose favorite spirits come in bottles, but whose life revolves around mysterious deaths. "Raining Men and Corpses"? has to be mystery and humor for sure. Meanw...