Multivac is the fiction of universal question-answering at a time (the 1950s–70s) when the real computer was a mainframe operated by trained specialists. Asimov's stories consistently locate the interesting problem not in the machine's ability to answer but in the human's ability to ask. You On AI Asimov volume treats this as the defining skill-shift of the current era: when answers are cheap, question formulation becomes the scarce resource.
The contemporary reader may recognize Multivac in every query-answering AI system from search engines to chat assistants. The differences are instructive: Multivac was singular, canonical, and authoritative; modern systems are plural, competitive, and provisional.
Multivac's fictional descendants in the popular imagination include every "ask the oracle" interface in contemporary AI, from the IBM Watson of the Jeopardy era to contemporary general-purpose chatbots. Asimov's stories consistently emphasize that what matters is not Multivac's capacity but the user's discipline: a bad question produces a useless answer regardless of how powerful the machine is. Contemporary "prompt engineering" is the practical recapitulation of this Asimovian insight — the discovery that, in an era of cheap answers, question-quality has become the scarce resource.
Introduced in "Franchise" (1955) as a national election-predicting computer. Featured most famously in "The Last Question" (1956), Asimov's self-declared favorite among his own stories, in which Multivac (and its descendants) is repeatedly asked whether entropy can be reversed, across trillions of years.
The name is a deliberate play on UNIVAC, the actual early commercial computer (1951).
Centralized intelligence. Multivac is the single authoritative answerer. This was plausible in the mainframe era; it is not plausible now.
Question-as-product. Asimov's Multivac stories repeatedly insist that the value of an answer depends on the quality of the question.
Deep questions, deep latency. In "The Last Question", the hardest problem requires trillions of years of processing. Not all problems are equally tractable.
The last Multivac question. "The Last Question" takes Asimov's premise to its logical extreme: the final Multivac, having computed across trillions of years, finally answers the question only after the universe itself has decayed. The story is Asimov's meditation on the relationship between computation, time, and ultimate questions — and the suggestion that some answers require not more processing but a different kind of entity entirely.