A perfect essay is a rare event. Here's an example. The playwright Sarah Ruhl is alarmed; a scream is coming from her daughter's room. It turns out the daughter has just discovered dramatic irony. "I know something that the Little Princess does not--and this feeling is the worst." Having claimed to be terrified, Daughter happily keeps turning the pages. Sarah then considers her own distaste for dramatic irony--and links this feeling with death, which is "the ultimate form of this particular species of irony." God holds all the cards; God knows when you will die, and God isn't saying. More spirited than Sarah, Daughter has a solution. It's possible to cheat death. Just look at dolls; they get "old," but they do not age. Take that, God. This is a terrific essay for a few reasons. First, it's consistently surprising. Second, it shows two versions of insanity: one belongs to the bullheaded daughter, but another belongs to Sarah Ruhl. (W...