The large houses fit in the universe of Dune as the noble families which are organised around the Landsraad. The big houses are holders of one or more planets that specialize in certain areas (Agriculture, machinery, trade, etc) administered as a feudal system being, led by a noble (Duke, Conde and other titles of nobility). The saga of Dune is mainly focused on the characters of House Atreides , the House Harkonnen and House Corrino, latter being which governs the known universe.
Other large houses in the Dune books are the Bene Tleilax, House Richese, House Vernius…
There are also the so-called lower houses
After the revolution the Jihad Butleriano, human computers, computer science in general and any form of artificial intelligence, they were taboo. So the complexity of a galactic civilization fell into human hands. It was the Mentat home that picked up the challenge to make a human being capable of carrying out all the necessary calculations for accounting and the predictions are need of continued. The Mentat develop their logical abilities, analytical and synthesis to such an extent that even the less seasoned Mentat could easily overcome any computer created by man.
The Mentat, However, soon discovered that achieve this goal supposed to regret losing a bit of humanity.
The States of trance in which the calculation Mentat is possible are induced by spice, drug that also lengthens life.
The ghola are clones of dead living. The Bene Tleilax developed procedures for, from still-living material of a newly dead, get a clone physically identical with accelerated growth. At the beginning of Dune the ghola are nothing more than copies of the dead person physical, but soon the Tleilaxu discover the way to recover the genetic memory stored in their cells, restoring all the memories and personality of the person until the moment before his death, Although the process is extremely painful and traumatic for the ghola. The process does not eliminate the experiences and memories of the ghola so far, these mixed with its own past.
The ghola fit more or less into the desire or human fear that copies of ourselves might have something of our vital breath, and that they therefore pose some kind of immortality. To Herbert also served him to model a quite interesting home, of the Tleilaxu. Themselves, the Tleilaxu masters, Once discovered the secret of the recovery of the genetic memory, apply it in secret about themselves to enhance their plans of religious conquest of the universe.
Not only ghola were a copy, but they were also “improved” with a few special abilities who liked to add purely for fun and practicality. As is the case with other products of the Bene Tleilax, the ghola arouse fear and mistrust not knowing what may be ocultadao the Tleilaxu in your body or your mind.
The most famous ghola Duncan Idaho was, that it was copied by the Dios Emperador one and again to call him at his service and self-destruct after entering into an ethical conflict between his devotion by the House Atreides and the acts of the Dios Emperador. Other times, was the own Dios Emperador which eliminated these ghola in defence of his person.
Spice or Melange, It is a substance with geriatric and highly addictive qualities. It is only on the planet Arrakis, also known as Dune ,name given by the Fremen inhabitants. On Arrakis spice extraction is difficult to achieve, Since this is interspersed with sand and we must count on machinery specialized both on land and in the air. Extraction is hazardous because of sand worms that come to any rhythmic vibration and therefore, where are the Spice harvesters, attacking them.
It is well known that overdoses of spice generate altered mental States, it allow to expand the consciousness.
The importance of the spice is vital to the survival of the universe, Since the navigators of the Cofradía Eapacial need it to carry out the >space travel.