A man who has built an identity out of a costume (the robes, the dark glasses, the invented academic field) and is terrified that the costume is all there is. His fear of death is simultaneously his most relatable and most absurd quality: universal and neurotic, justified and comic. Jack does not grow or change by the novel's end — DeLillo refuses that consolation. He remains the same fearful, loving, self-deceiving man, slightly more aware of his self-deception.