they can perform complex logical computations that are superior to those of the ancient thinking machines. The Bene Tleilax are amoral merchants who traffic in biological and genetically engineered products such as artificial eyes, "twisted" Mentats, and gholas. Finally, the Ixians produce cutting-edge technology that seemingly complies with (but pushes the boundaries of) the prohibitions against thinking machines. The Ixians are very secretive, not only to protect their valuable hold on the industry but also to hide any methods or inventions that may breach the anti-thinking machine protocols. Against this backdrop, the Prelude to Dune prequel trilogy (1999–2001) chronicles the return from obscurity of House Atreides, whose role in the Butlerian Jihad is all but forgotten. The Imperial House schemes to gain full control of the Empire through the control of melange, precisely at the time that the Bene Gesserit breeding program is nearing fruition. The rise of the Atreides As Frank Herbert's Dune (1965) begins, Duke Leto Atreides finds himself in a dangerous position. The 81st Padishah Emperor, Shaddam IV, has put him in control of the desert planet Arrakis, known as Dune, which is the only source of the all-important spice melange. The most valuable commodity in the known universe, the spice not only makes safe and reliable interstellar travel possible, but also prolongs life, protects against disease, and is used by the Bene Gesserit to enhance their abilities. The potential financial gains for House Atreides are mitigated by the fact that mining melange from the desert surface of Arrakis is an expensive and hazardous undertaking, thanks to the treacherous environment and constant threat of giant sandworms that protect the spice. In addition, Leto is aware that Shaddam, feeling threatened by the rising power and influence of the Atreides, has sent him into a trap. Failure to meet or exceed the production volume of his predecessor, the villainous Baron Vladimir Harkonnen, will negatively affect the position of House Atreides in CHOAM, which relies on spice profits. Further, the very presence of the Atreides on Arrakis inflames the long-simmering War of Assassins between House Atreides and House Harkonnen, a feud ignited 10,000 years before when an Atreides had a Harkonnen banished for cowardice after the Butlerian Jihad. The little-understood native population of Arrakis are the Fremen, long overlooked by the Imperium. Considered backward savages, the Fremen are an extremely hardy people and exist in large numbers, their culture built