Kurt Vonnegut’s “Slaughterhouse-Five” is humane enough to allow, at the end of the horror that is its subject, for the possibility of hope.Photograph by Santi Visalli / Getty I first read “Slaughterhouse-Five” in 1972, three years after it was published and three years before I published my own first novel. I was twenty-five years old. 1972 was the year of inching slowly toward the Paris Peace Acc