Arrakis (əˈrɑːkᵻs)—informally known as Dune and later called Rakis—is a fictional desert planet featured in the Dune series of novels by Frank Herbert. Herbert's first novel in the series, 1965's Dune, is considered one of the greatest science fiction novels of all time, and it is sometimes cited as the best-selling science fiction novel in history.
In Dune, Arrakis is the most important planet in the universe, as it is the only source of the drug melange. Melange (or, "the spice") is the most essential and valuable commodity in the universe, as it extends life and makes safe interstellar travel possible (among other uses). Harvesting the spice is also hazardous in the extreme, due to both the harsh climate of the planet and the fact that melange deposits are guarded by giant sandworms.
Arrakis is also the home of the Fremen (Zensunni wanderers), and subsequently is the Imperial Capital of the Atreides Empire. Arrakis is the third planet orbiting the star Canopus, and it in turn is orbited by two moons, one of which has an albedo pattern resembling the desert kangaroo mouse, Muad'Dib, on it; the other moon has markings resembling a human hand.
A desert planet with no natural precipitation, in Dune it is established that Arrakis had been "His Imperial Majesty's Desert Botanical Testing Station" before the discovery of melange, for which it is the only natural source in the universe. Melange (or, "the spice") is the most essential and valuable commodity in the universe, as it extends life and makes safe interstellar travel possible (among other uses). The planet has no surface water bodies, but open canals called qanats are used "for carrying irrigation water under controlled conditions" through the desert. The Fremen collect water in underground reservoirs to fulfill their dream of someday terraforming the planet, and pay the Spacing Guild exorbitant fees in melange to keep the skies over Arrakis free of any satellites which might observe their efforts.