Moby-Dick; or, The Whale is a novel by Herman Melville, first published in 1851. It is considered to be one of the Great American Novels and a treasure of world literature. The story tells the adventures of wandering sailor Ishmael, and his voyage on the whaleship Pequod, commanded by Captain Ahab. Ishmael soon learns that Ahab has one purpose on this voyage: to seek out Moby Dick, a ferocious, enigmatic white sperm whale. In a previous encounter, the whale destroyed Ahab's boat and bit off his leg, which now drives Ahab to take revenge. In Moby-Dick, Melville employs stylized language, symbolism, and the metaphor to explore numerous complex themes. Through the journey of the main characters, the concepts of class and social status, good and evil, and the existence of God are all examined, as the main characters speculate upon their personal beliefs and their places in the universe. Moby-Dick is now considered part of the Western canon, and at the center of the canon of American novels.