As murder story writers assume, and as most of us learn in experience, we have in us capacities for fury, fear, envy, greed, conceit, callousness, and hate which, given the right provocation, could make killers out of us all--baby-batterers or Bluebeards, professional thugs or amateur hit men.

G. K. Chesterton's Father Brown explained his method of detection by saying, "You see, it was I who killed all those people"--in the sense that he looked within himself to find the mentality that would produce the crime he was investigating, and did in fact discover it there. Chesterton lets him moralize: "No man's really any good till he knows how bad he is, or might be; till he's realized exactly how much right he has to all this snobbery, and sneering, and talking about 'criminals,' as if they were apes in a forest ten thousand miles away ... till he's squeezed out of his soul the last drop of the oil of the Pharisees; till his only hope is somehow or other to have captured one criminal, and kept him safe and sane under his own hat."

Brown, though fictitious, states fact. When the fathomless wells of rage and hatred in the normal human heart are tapped, the results are fearful. "There but for the grace of God go I." Only restraining and renewing grace enables anyone to keep the sixth commandment.