Clear definitions for the people, places, ideas, and technology that connect Asimov's Robot, Empire, and Foundation stories. Book canon comes first; television inventions are labeled directly.
29 terms · Reviewed September 2026 · Sources listed with every definition
Anacreon is one of the Four Kingdoms that form near Terminus as Imperial authority collapses. Its attempt to seize the Foundation creates the first Seldon Crisis resolved by Salvor Hardin.
Primary reference: Foundation — The Encyclopedists and The Mayors
Atomics is Asimov's broad term for nuclear power and devices. The Foundation preserves and miniaturizes atomic technology after neighboring worlds lose the knowledge to maintain it, turning science into political and economic leverage.
Primary reference: Foundation — The Mayors and The Merchant Princes
Cleon is the name of two emperors in the novels: Cleon I, who rules during Hari Seldon's life in the prequels, and Cleon II, who recalls the general Bel Riose in Foundation and Empire. The line of cloned Cleons is an invention of the Apple TV+ adaptation, not a feature of Asimov's novels.
Primary reference: Prelude to Foundation, Forward the Foundation, Foundation and Empire; Apple TV+ adaptation distinction
Eto Demerzel is the identity used by the robot R. Daneel Olivaw while serving as First Minister to Emperor Cleon I. The Apple TV+ series reimagines Demerzel while preserving the character's connection to the Empire.
Primary reference: Prelude to Foundation and Forward the Foundation
The Encyclopedia Galactica is the Foundation's public founding project: a collection intended to preserve human knowledge before the Empire falls. Hari Seldon later reveals that it was also a cover for establishing the First Foundation on Terminus.
Primary reference: Foundation — The Encyclopedists
The First Foundation is the community of scientists established on Terminus to preserve physical knowledge and become the nucleus of a future Second Galactic Empire. Most members begin without knowing their deeper role in the Seldon Plan.
Primary reference: Foundation and Second Foundation
The Galactic Empire is the civilization that governs millions of inhabited worlds from Trantor. By Hari Seldon's era it still appears powerful, but psychohistory shows that its institutions, technology, and political control are already decaying.
Primary reference: Foundation series
Gaia is a planet whose people, animals, plants, and matter participate in a shared group consciousness. It offers Golan Trevize a third path between rule by the First Foundation and guidance by the Second Foundation.
Primary reference: Foundation's Edge and Foundation and Earth
Galaxia is the proposed future in which the entire galaxy becomes a single shared consciousness modeled on Gaia. Golan Trevize chooses it as humanity's long-term direction, though the transformation has barely begun by the end of Foundation and Earth.
Primary reference: Foundation's Edge and Foundation and Earth
The Genetic Dynasty is the Apple TV+ show's system of rule by three cloned emperors — Brother Dawn, Brother Day, and Brother Dusk — all derived from Cleon I. It does not appear in Asimov's books.
Primary reference: Apple TV+ Foundation
The Imperial Library is Trantor's great repository of knowledge. It survives the Sack of Trantor, and in Foundation and Empire Ebling Mis searches its records for the Second Foundation. The Apple TV+ series makes the Library the Second Foundation's hiding place.
Primary reference: Foundation and Empire; Apple TV+ Foundation
The Jump is faster-than-light travel through hyperspace. In the novels, calculations determine a ship's safe route; the Apple TV+ series gives the process a more visual form and often relies on specialized navigation technology.
Primary reference: Foundation novels; Apple TV+ adaptation distinction
Mentalics is the ability to perceive and alter human emotions and mental states. The Mule possesses an exceptional natural form, while members of the Second Foundation develop related abilities through disciplined training.
Primary reference: Foundation and Empire and Second Foundation
The Mule is a mutant conqueror who can reshape emotions. Because psychohistory predicts populations rather than singular individuals, his rise disrupts the Seldon Plan and becomes its greatest unforeseen crisis.
Primary reference: Foundation and Empire and Second Foundation
The Periphery is the outer rim of the Galactic Empire, where imperial control and technical knowledge decline first. Terminus lies at its edge, surrounded by kingdoms like Anacreon that break away as the Empire withdraws.
Primary reference: Foundation
The Prime Radiant is the device through which Hari Seldon and later psychohistorians display, examine, and revise the equations of psychohistory. Its detailed visual behavior in the Apple TV+ series is an adaptation expansion.
Primary reference: Foundation novels and Apple TV+ Foundation
Psychohistory is Hari Seldon's fictional mathematical science for predicting the behavior of very large populations. It cannot reliably predict individuals, and its subjects must remain unaware of detailed forecasts for the equations to hold.
Primary reference: Foundation series
R. Daneel Olivaw is a humaniform robot first introduced in Asimov's Robot novels. Across roughly twenty thousand years, he works behind the scenes to protect humanity and eventually connects the Robot, Empire, and Foundation stories.
Primary reference: The Caves of Steel through Foundation and Earth
The Three Laws of Robotics require a robot to avoid harming humans, obey human orders unless that conflicts with the First Law, and protect itself unless that conflicts with the first two laws. Later stories add the Zeroth Law concerning humanity as a whole.
Primary reference: Asimov's Robot stories and Robots and Empire
The Second Foundation is Seldon's hidden community of psychohistorians and mentalic specialists. It monitors the Seldon Plan, makes minimal corrections when necessary, and is eventually revealed to be based on Trantor.
Primary reference: Second Foundation
A Seldon Crisis is a historical turning point predicted by psychohistory in which social pressures leave the First Foundation with one viable path forward. Seldon's recorded appearances explain each crisis only after its decisive moment arrives.
Primary reference: Foundation
The Seldon Plan is a thousand-year strategy designed to reduce the dark age after the Galactic Empire's fall from thirty thousand years to one thousand. It depends on the complementary development of the First and Second Foundations.
Primary reference: Foundation series
Spacers are descendants of early settlers on worlds beyond Earth in the Robot era. Their societies use robots extensively and often extend human life, but their low populations and isolation leave them vulnerable to long-term decline.
Primary reference: Robot novels and Robots and Empire
Star's End is the cryptic location Hari Seldon gives for the Second Foundation. The phrase points not to the physical edge of the galaxy but to Trantor, the former center where the Empire's political stars metaphorically ended.
Primary reference: Second Foundation
Terminus is the resource-poor planet at the galaxy's edge where the First Foundation is established. Its isolation protects the colony, while its lack of metals forces it to develop compact technology and influence neighboring worlds through knowledge and trade.
Primary reference: Foundation series
The Time Vault is the chamber on Terminus where recorded images of Hari Seldon appear at predicted historical moments. The floating Vault and its null field in the Apple TV+ series are adaptation inventions.
Primary reference: Foundation; Apple TV+ adaptation distinction
Trantor is the planet-wide city and administrative capital of the Galactic Empire. Its dependence on imported food and enormous bureaucracy make it both the height of imperial power and a symbol of the Empire's fragility.
Primary reference: Foundation series
In the Apple TV+ adaptation, the Vault is a mysterious structure on Terminus that contains a digital Hari Seldon and projects a null field. It is the show's reinterpretation of the novels' much simpler Time Vault recordings.
Primary reference: Apple TV+ Foundation
The Zeroth Law states that a robot may not harm humanity, or through inaction allow humanity to come to harm. It takes priority over the Three Laws but forces robots to judge an abstract collective good rather than the safety of one person.
Primary reference: Robots and Empire