Jessica Atreides is a key fictional character in the science-fiction novel Dune, by Frank Herbert. Jessica also plays an important role in the sequels, Dune Messiah and Children of Dune.
Jessica was conceived through the seduction of the Baron Vladimir Harkonnen by Reverend Mother Gaius Helen Mohiam, and born to the Bene Gesserit in the year 10,154 after the formation of the Spacing Guild. She was raised to be married to the Duke Leto Atreides, and instructed to produce a daughter, but no sons, for him. This daughter would be bred to Feyd Rautha, nephew of Baron Vladimir Harkonnen and heir to House Harkonnen, healing the generations old rift between House Atreides and House Harkonnen, and producing the Kwistaz Haderach for the Bene Gesserit. The Kwisatz Haderach is the male reverend mother who has other memories of his male line, something the all-female Bene Gesserit lack, along with the female line.
However, Jessica falls in love with Leto, and produces a son for him, Paul (there is some indication that Jessica believed she could achieve the Kwisatz Hadderach herself, one generation early). Paul is the Kwisatz Haderach, and eventually sets the Imperium on a course lasting thousands of years in the person of his son, Leto Atreides II. Much to the frustration of the Bene Gesserit, they do not control Paul, and the events of the coming millennia leave Jessica noteworthy as a figure of history who committed a great wrong (according to the Bene Gesserit); in the coming centuries, for a Bene Gesserit to choose her love over the instructions of her order is known as "the Jessica Crime".
In Dune, House Atreides is given the planet Arrakis in fief-complete, taking possession from House Harkonnen of the only melange-producing world in the Imperium. The change of fief is a trap, though: shortly after committing themselves there, House Harkonnen and the Emperor invade (with the Emperor's sardaukar disguised as Harkonnen soldiers); the betrayal of the Duke by the family's doctor, Dr. Wellington Yueh, completes the plan, and House Atreides is destroyed in place. Paul and Jessica narrowly escape to the desert, finding refuge with the Fremen thanks to the legends planted there by the Bene Gesserit's Missionaria Protectiva, which practices religious engineering. Jessica casts Paul as the Lisan al'Gaib, the messiah, and herself as the reverend mother who shall bring him, even though she hasn't experienced the spice agony that transforms an acolyte into a full reverend mother.
The Fremen provide not only refuge, but also an army with which Paul can retake the planet and restore his house. The Fremen also have 'wild' reverend mothers, women who undergo the spice agony to awaken their other memories. Hiding in Stilgar's seitch, their reverend mother about to die and with the seitch about to travel into the desert, Jessica accepts the ritual of the spice agony and becomes the sayyadina of the tribe. Unfortunately, Jessica is pregnant with the Duke's daughter, Alia Atreides. For a fetus to undergo the spice agony results in abomination: because the spice agony awakens the ego-memories of one's ancestors, the 'pre-born' become possessed eventually by one of their forbears, since they lack a coherent personality of their own. Jessica is the daughter of the Baron Vladimir Harkonnen. In Children of Dune, this is the ego-memory that will possess Alia, leading her to attempt the complete destruction of the restored House Atreides while she rules it as regent.
In Dune Messiah, Jessica has returned to Caladan, the ancestral home of the Atreides. She has also, by some accounts, returned to the Sisterhood following the death of her Duke, and while she cannot influence Paul, she does act as distant counselor.
In Children of Dune, Jessica returns to Dune to inspect Paul's children, Leto Atreides II and Ghanima, to see if they can be returned to the control of the sisterhood. Realizing that Alia is fully possessed, Jessica survives an assassination attempt by Alia and flees to the desert once more, taking refuge with Stilgar in his seitch. A civil war has divided Arrakis, with Fremen revolting against the transformation of the desert started by Paul. Alia's husband, Duncan Idaho, also realizes that Alia is possessed. When Alia instructs Duncan to make her mother disappear, Duncan kidnaps her on the orders of the Preacher, a mysterious desert figure that some suspect is Paul Atreides, who disappeared into the desert. Duncan takes her to Salusa Secundus, the home of House Corrino and the previous emperor, where the Preacher has told Jessica, through Duncan, to train the pupil she finds there: Prince Farad'n. She trains him in the Bene Gesserit way, and at the end of Children of Dune, he marries Ghanima and becomes Leto's imperial scribe. Jessica died in year 10,256 after 102 years of life.