Narrated by the sailor Ishmael, Moby-Dick is the tale of the maniacal quest of Ahab, captain of the whaling ship Pequod , as he seeks vengeance against Moby-Dick, the giant white sperm whale that bit off his leg on the ship's previous voyage. More than an epic sea-story, the detailed and realistic descriptions of whale hunting and the process of extracting whale oil, as well as life aboard ship among a culturally diverse crew, are mixed with exploration of class and social status, good and evil, and the existence of God.