My first encounter with an unreliable narrator—that I recognized, that is—was years ago when I first read Agatha Christie’s notorious The Murder of Roger Ackroyd, first published in 1926. The ending stunned me as it has many other readers through the years. It also gave rise to a list of rules for writing mysteries formulated by mystery author John Dickson Carr, rebuttals to that list from other authors, and an essay by the well-known literary critic Edmund Wilson entitled “Who Cares Who Killed Roger Ackroyd?”