It chronicles the wanderings and teachings of a philosopher, self-named Zarathustra after the founder of Zoroastrianism in ancient Persia. It uses a poetic, fictional form, often satirizing the New Testament, to explore many of Nietzsche's ideas.
Central to Zarathustra is the notion that human beings are a transitional form between apes and what Nietzsche called the Übermensch, literally "Over-person," usually translated as "Overman." The name is one of the many puns in the book and refers most clearly to the image of the sun coming over the horizon at dawn as well as the basic notion of overcoming.
Largely episodic, the stories in Zarathustra can be read in any order. Zarathustra contains the famous statement, "God is dead."
Also sprach Zarathustra is also the title of a symphonic poem by Richard Strauss, composed in 1896 and inspired by the book. It is best known for its use in Stanley Kubrick's 1968 film 2001: A Space Odyssey. The opening "Dawn" section is used three times, most famously in the opening title sequence.
See also: Übermensch