Does science fiction predict the future or does it merely inspire future discoveries?
That's the question these 15 books force readers to ask themselves as they read about computer hackers, bionic limbs, and iPads, all thought up by authors decades and sometimes centuries before the inventions were created.
Inspired by this infographic of seemingly precognitive sci-fi books, we've assembled a list of the books that predicted the future.
Keep scrolling to see.
Jonathan Swift's "Gulliver’s Travels" predicted the discovery of Mars’ two moons
This 1726 social satire follows a man named Gulliver as he travels into different worlds, like one occupied by tiny humans or another inhabited by giants.
But when Gulliver is on the island of Laputa, a floating world filled with scientists, the astronomers notice Mars has two moons in its orbit. Over 150 years later in 1877, it was discovered Mars did indeed have two moons— Phobos and Deimos.
Mary Shelley's "Frankenstein" predicted modern transplants.
When Shelley wrote "Frankenstein" in 1818, science was just beginning to explore the new realm of dead tissue reanimation through electricity.
And while the early methods were crude to say the least, they paved the way for future medical breakthroughs like organ transplants that were envisioned in Shelley's novel.
Jules Verne's "Twenty Thousand Leagues Under the Sea" predicted the electric submarine.
Jules Verne is known as one of the most forward-thinking authors of the 19th Century, predicting everything from lunar modules to solar sails over 100 years before they were invented.
His most famous book, however, is "Twenty Thousand Leagues Under the Sea." Published in 1870, the novel predicted electric submarines 90 years before they were officially invented.
Edward Bellamy's "Looking Backward" predicted credit cards.
63 years before credit cards were invented, Bellamy had a similar idea in his 1888 Utopian science fiction novel.
After Julian West falls asleep for 113 years and wakes up in the year 2000, he finds that everyone uses "credit" cards to buy goods. Though the way Bellamy's cards work is closer to a debit card or Social Security dividend, it remains nonetheless an interesting prediction.
Hugo Gernsback's "Ralph 124C 41+" predicted solar power
This early novel by Hugo Gernsback — the man the sci-fi Hugo Book Awards are named after — was written in 1911, but set in the year 2660.
Though this story isn't quite as exciting as modern sci-fi books due to its weaker plot and formulaic love story, it did predict solar energy, TVs, tape recorders, movies with sound, and space travel.
H. G. Wells' "The World Set Free" predicted the atomic bomb
Though the atomic bomb in Wells' universe was a uranium hand grenade — not unlike a regular bomb, but with more radiation — the science behind the idea was still roughly three decades ahead of its time.
Aldous Huxley's "Brave New World" predicted mood-boosting pills.
This dystopian novel pictures what would happen if the world became a drug-dependent capitalistic society that values sexual freedom over monogamy and separates people into a caste system.
In his 1931 book, Huxley foresaw the use of mood-boosting pills and reproductive technology, and the problems of overpopulation.
George Orwell's "1984" predicted Big Brother and mass surveillance
Orwell's "1984" is the classic dystopian novel that is responsible for concepts like Big Brother, doublethink, Newspeak, and the Thought Police.
Written about a dystopian world nearly 40 years after World War II, the book focuses on topics like censorship, propaganda, and oppressive government in a futuristic society. Orwell also predicted mass surveillance and police helicopters in this 1949 classic.
Ray Bradbury's "Fahrenheit 451" predicted earbuds
Bradbury wrote "Fahrenheit 451" in 1953 about a technophile society where books are outlawed and any books that still exist are burned.
His dystopian world predicted flat-screen TVs as well as "seashells" and "thimble radios," which were portable audio devices not unlike earbuds and Bluetooth headsets.
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Robert Heinlein's "Stranger in a Strange Land" predicted the waterbed.
This 1961 novel follows Valentine Michael Smith after he finally comes home to Earth after being raised by Martians since he was a child.
In addition to discussing futuristic topics such as intergalactic politics, "Stranger in a Strange Land" also predicted waterbeds a decade before they came to fruition.
Arthur C. Clarke's "2001: A Space Odyssey” predicted the iPad.
This 1968 sci-fi book about an alien civilization creating intelligent life on Earth is filled with serious themes like nuclear war, evolution, and the perils of artificial intelligence in the form of the super computer HAL 9000.
But the most accurate prediction from the book were the electronic papers or the "newspad" that people read, which sounds an awful lot like the iPad.
John Brunner's "Stand on Zanzibar" predicted satellite TV and electric cars.
This dystopian novel was first published in 1968 and takes place in 2010. In Brunner's novel, the United States is grappling with overpopulation and widening social divides.
Aside from the realistic plot, the book predicted quite a few technologies we have today, including on-demand TV, satellite TV, laser printers, electric cars, and even the decriminalization of marijuana.
Martin Caidin's "Cyborg" predicted the first bionic limb.
This 1972 novel follows former-astronaut-turned-pilot Steve Austin, who crashes during a flight, leaving him with only one limb and blind in one eye.
A team of scientists are able to give Austin new legs, a removeable eye with a camera, and a bionic arm, which makes him a "cyborg," or a mixture of man and machine. The book prophesied the first bionic leg transplant by 41 years.
Douglas Adams' "The Hitchhiker’s Guide to the Galaxy" predicted audio translating apps
Published in 1979, Arthur Dent is warned by his friend Ford Prefect — a secret researcher for the interstellar travel guide "The Hitchhiker's Guide to the Galaxy" — that Earth is about to be demolished.
The pair escapes on an alien spaceship, and embarks on a bizarre adventure around the universe. One of the things they witness is real-time audio translations with the universal translator, now a reality 34 years later thanks to translation apps.
William Gibson's "Neuromancer" predicted cyberspace and computer hackers
This futuristic crime caper from 1984 follows a burnt-out hacker and cyber thief whose ability to "jack in" to cyberspace is restored by a miracle cure.
"Neuromancer" was not only the first novel to win the triple crown of sci-fi awards (the Hugo Award, the Nebula Award, and the Philip K. Dick Award) and inspired the "Matrix" series, but also predicted our future cyberspace society and computer hackers.