I see poisoners--so calculating, so cold-blooded--as most like the villains of our horror stories. They're closer to that lurking monster in the closet than some drug-impaired crazy with a gun. I don't mean to dismiss the latter--both can achieve the same awful results. But the scarier killer is the one who thoughtfully plans his murder ahead, tricks a friend, wife, lover into swallowing something that will dissolve tissue, blister skin, twist the muscles with convulsions, knows all that will happen and does it anyway.