It all began with an early obsession with Nancy Drew, then I moved on to Sherlock Holmes and Agatha Christie, and before I knew it I was devouring any book that promised thrills, intrigue, and murder. Is there a detective in it? I'll read it. Bonus points if the protagonist is a woman. And the cherry on top is if the author is British or Scandinavian (or Irish). That said, Gone Girl is one of my favorite books of all time, so if you feel the same, you'll probably love my other picks. Obviously, this isn't an exhaustive list — I've only included books I can vouch for (aka that I've read) — but here are 21 modern mysteries guaranteed to keep you up all night, in order of tame to terrifying.