In writing this song, Mick Jagger and Keith Richards of the Rolling Stones used several poetic conventions to pack a lot of power in the lyrics. For example, the entire song is a dramatic monologue in the tradition of Robert Browning's "My Last Duchess." That is, the songwriters have created a persona--in this case, unnamed--who exposes his weaknesses through his own words. In his references to his own "darkness" and his desire to see this despair spread to the outside world, he reveals that he is mentally ill, perhaps chronically depressed. Furthermore, his comment that he "could not foresee this thing happening to you" leaves us wondering whether he his darkness has resulted in some violent acts, including one committed against his loved one. Imagery plays an important role in the song. The speaker wants to replace red--associated with blood, life, love, and passion--with black, which we sometimes associate with night, evil, death, and ruin. In the references to black, the speaker further compounds the effect by using some similes comparing the black to the color of night and coal. Because these similes are clichés, however, they do not carry much power. Some of the key symbols in the song are the door, which suggests means and hope, and the setting sun, which points to death and endings. Finally, the music that accompanies the lyrics effectively complements them. The insistent repetition in the opening part of the song sets the stage for the monologue of a man haunted by recurring dark thoughts. Furthermore, the song has an eerie, exotic quality because the dominant instrument is a sitar, an Indian instrument that sounds otherworldly to my Western ears because we don't hear it very often in the United States.