Besides exploring the close affinity between Nietzsche and Freud—"these two voices from the underground"—Roazen raises the stimulating question of the past tendency to "prettify" Freud. He notes not only a paucity of studies regarding the possible association between Nietzsche and Freud, but also the tendency to ignore such aspects of Freud's thinking as the death instinct, his suspicion of the ideal of altruism, and his cynicism about human rationality and morality. Not only is Freud's indebtedness to Nietzsche far more direct than has been recognized, but his own pessimistic thinking has been covered over by a tendency to highlight the more positive aspects of psychotherapy and psychoanalysis. Says Roazen, "We must take the savage side of Freud along with the rest of him."