Past Kindle Book Deals but Still Must Read Books!
Looking for must read books you missed the first time around? You’re in the right place. This is where all of our past Kindle book deals live—the ones good enough to click, even if the discount’s gone. Every book here was hand-picked by our team, featured in a daily deal, and still earns a spot on your TBR.
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These Books Earned Our Seal of Approval—Snag Them Before They Vanish (Again)
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959 past books matching Sci-Fi
Best for readers who like fantasy LitRPG, final-book stakes, city sieges, power progression, and battles where survival is not the only question.
Light’s Ascension
LitRPG · Sci-Fi
Our take
Light’s Ascension concludes the Exlian Syndrome Series as Mark faces the Exlian assault on New Emery, rising infighting among the defenders, and the cost of completing his evolution. Best for readers who like fantasy LitRPG, final-book stakes, city sieges, power progression, and battles where survival is not the only question.
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About the book
From bestselling LitRPG author Seth Ring—creator ofThe Titan series and Battle Mage Farmer—Light’s Ascension is the final book in the epic Exlian Syndrome Series.
The unstoppable wave arrived, and Mark and his friends were unable to stop it. As the Exlian assault the city of New Emery, everything starts to spiral out of control. Forces bent on taking advantage of the situation emerge from every corner, and soon the infighting among the defenders becomes an even greater threat than the Exlian themselves.
Yet in the midst of danger, there lies opportunity. Realizing that he could take advantage of the situation to complete his evolution and become a being of unparalleled power, Mark must answer a simple question: Is there a cost too great to pay?
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Good for readers who want idea-driven sci-fi with alien mysteries, high-stakes discovery, and questions about humanity’s place in the universe.
Frequency 2
Sci-Fi · First Contact · Hard Sci-Fi · Techno-Thriller
Our take
From multimillion-copy international bestselling authors Douglas E. Richards and Joshua T. Calvert, Frequency 2 follows parallel missions from Patagonia to Europa as strange signals, synchronized brainwaves, and an alien rescue push humanity toward a new understanding of consciousness and first contact. Good for readers who want idea-driven sci-fi with alien mysteries, high-stakes discovery, and questions about humanity’s place in the universe.
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About the book
A desperate race to revive an alien buried on an icy moon. A fringe cult tuned into signals from the stars. And two extraordinary women willing to risk everything to forge humanity’s destiny.
The second and final entry in the electrifying series from multimillion-copy international bestselling authors Douglas E. Richards and Joshua T. Calvert.
Four years after the world-changing events of Frequency, the fragile hope born on Europa has fractured under cults, conspiracy theories, and misread alien wisdom. When a remote group in Patagonia begins displaying synchronized brainwave patterns that match nothing on Earth, Alexandra and Ethan Calloway race to investigate. What they find is astonishing: signals from a distant star system channeled through something hidden in the Patagonian wilderness—something that shouldn’t exist.
On Jupiter’s frozen moon, Milo Daven and Elena Vasquez lead a desperate mission to reach the alien whose message changed the world. In an environment that makes Antarctica seem like paradise, they’ll attempt the unthinkable: a rescue that could rewrite humanity’s place in the universe.
As parallel threads of discovery converge, Alexandra, Elena, and their teams confront questions that push the boundaries of science, consciousness, and the interconnectedness of all things. Are we ready for what comes next?
A mind-bending journey into hidden frequencies that bind minds across worlds, Frequency 2 delivers the jaw-dropping payoff to one of the most visionary first-contact series ever written.
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Best for readers who like space opera with reckless pilots, alien mysteries, ancient threats, and high-stakes survival.
Crucible
Sci-Fi · Cyberpunk
Our take
Crucible follows Kaiden Jericho and his EI partner, Chief, as an ancient alien signal leads them to a graveyard of destroyed civilizations and a predator waiting at the galaxy’s edge. Best for readers who like space opera with reckless pilots, alien mysteries, ancient threats, and high-stakes survival.
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About the book
Kaiden Jericho has made a career out of bad decisions. This one might be his last.
Flying into the part of space the cartographers literally labeled "suicide" wasn't Kaiden Jericho's worst call. It cracked the top five, though.
An ancient alien signal said something was waiting at the galaxy's edge, so naturally Kaiden pointed the Resolute straight at it. What's waiting turns out to be a graveyard—eighty civilizations smarter, older, and far better armed than humanity, every one of them reduced to ash by something that hunts along a scar through the void and has never once needed to hurry.
His EI partner, Chief, calls it the Harvester. Kaiden calls it a very good reason to turn around. Except the Trinity fleet is shadowing them as expendable bait, the dead zone keeps whispering, and the thing in the dark has noticed someone is finally listening.
A street kid and a damaged orb against the predator that ended worlds. Those are the odds. They've survived worse on less.
Does the bond no one thought possible hold the one weapon that works—or just buy the galaxy one more name to forget?
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Good for readers who want sci-fi adventure with ancient alien wars, AI, survival upgrades, and reluctant captains.
Starship Superior
Sci-Fi · Galactic Empire · Military Sci-Fi
Our take
Starship Superior follows Owen Lake, a Lake Superior boat captain who is pulled aboard an advanced unmanned spacecraft and forced into a 100,000-year-old cosmic conflict after an AI bargain leaves Mari and his dog Jack in stasis, with a 4.4-star rating from more than 1,000 Amazon reviewers. Good for readers who want sci-fi adventure with ancient alien wars, AI, survival upgrades, and reluctant captains.
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About the book
Owen Lake never had any interest in space.
After watching his astronaut mother die, he preferred the simple life of a boat captain on Lake Superior. But the simple life was never meant to last.
His charter business is failing, but an opportunity pops up in the form of Dr. Mariana Keller, who's interested in what lies beneath the waves: a mysterious, unnatural blue glow emanating from the depths.
Owen agrees to take her on a clandestine dive to an ancient shipwreck site. With his trusty canine companion Jack by his side, he sets out with Keller, but a simple dive turns into a fight for their lives when a beam pins Mari beneath the wreckage.
As Owen struggles to free her, he is ripped into an underwater hole and finds himself aboard a highly advanced, unmanned spacecraft.
The ship's powerful Artificial Intelligence, which Owen names Jefferson, asks Owen to become a temporary crew member in exchange for the rescue of Mari and Jack. He immediately agrees without a second thought.
After rescuing them, the AI places them in stasis and initiates a launch. With the ship jettisoning Owen, Mari, and Jack toward deep space and a cosmic conflict far beyond Earth's solar system, it's clear there's a lot more to becoming a crew member than Owen could have imagined.
Eleven months later, Owen awakens to discover that he's undergone involuntary biological enhancements that allow him to survive deep space. The enhancements grant him abilities far beyond human limits. But Jefferson's bargain remains absolute: Owen must cooperate and prove his worth on a millennia-old quest for revenge against the enemy Federation... or Mari and Jack will remain frozen forever.
Forced to lead, Captain Owen Lake must now fight a war that began 100,000 years before he was ever born.
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Best for readers who like military sci-fi, ancient mysteries, alien threats, and fast-moving action.
Ruins of the Earth
Sci-Fi · Genetic Engineering
Our take
A Marine Raider’s final mission before retirement sends him to Antarctica, where researchers uncover an ancient secret that opens a portal and unleashes a violent threat against Earth, with a 4.5-star rating from more than 3,600 Amazon reviewers. Best for readers who like military sci-fi, ancient mysteries, alien threats, and fast-moving action.
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About the book
A secret buried in the Antarctic.
A puzzle unsolved for thousands of years. And a Brooklyn-born Master Gunnery Sergeant who's royally pissed that he has to babysit the researchers sent to figure it all out.
Patrick "Wic" Finnegan's last op as a Marine Raider before retirement sends him to the frozen Ellsworth Subglacial Highlands. The only reason he's here? He owes a favor to an old friend—but that doesn't mean he has to like it. When Wic finally sees what the team has uncovered, he can't believe his eyes, nor is he prepared for the violence to come.
Soon, the portal opens and unleashes a storm of unbridled fury upon humanity. From the Antarctic tundra to the streets of Manhattan, Wic and his team will be pushed to their limits as they fight to hold back Earth's ultimate threat.
The odds are against them. Governments are toppling. And the Earth is falling into ruin.
Join bestselling authors Christopher Hopper and J.N. Chaney on what readers call a "non-stop, break-neck thrill ride into metaspace." For fans of District 9, Expeditionary Force, and Galaxy's Edge, this is one military sci-fi thriller you won't be able to put down, and the official prequel to the hit series Ruins of the Galaxy.
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The Feed imagines a world where constant connection collapses into fear, hunger, and suspicion.
The Feed
Dystopian · Techno-Thriller · Time Travel
Our take
The Feed imagines a world where constant connection collapses into fear, hunger, and suspicion. Tom and Kate survive the fall of the technology that once linked every thought and memory, but their fragile safety breaks when their young daughter disappears. This dystopian sci-fi thriller blends post-collapse survival, parental desperation, and a chilling question of identity and trust.
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About the book
Nick Clark Windo's "The Feed examines our addiction to technology through the lens of a bleak dystopia . . . A deft and extremely clever work of sci-fi."*
The Feed is accessible everywhere, by everyone, at any time. It instantaneously links us to all information and global events as they break. Every interaction, every emotion, every image can be shared through it; it is the essential tool everyone relies on to know and understand the thoughts and feelings of anyone and everyone else in the world.
Tom and Kate use the Feed, but Tom has resisted its addiction, which makes him suspect to his family. After all, his father created it. But that opposition to constant connection serves Tom and Kate well when the Feed collapses after a horrific tragedy shatters the world as they know it.
The Feed's collapse, taking modern society with it, leaves people scavenging to survive. Finding food is truly a matter of life and death. Minor ailments, previously treatable, now kill. And while the collapse has demolished the trappings of the modern world, it has also eroded trust. In a world where survival of the fittest is a way of life, there is no one to depend upon except yourself . . . and maybe even that is no longer true.
Tom and Kate have managed to protect themselves and their family. But then their six-year-old daughter, Bea, goes missing. Who has taken her? How do you begin to look for someone in a world without technology? And what happens when you can no longer even be certain that the people you love are really who they claim to be?
*Wall Street Journal bestselling author Joe Hart
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A strong match for readers drawn to classic science fiction about culture, belief, human identity, and transformative outsider perspectives.
Stranger in a Strange Land
Sci-Fi
Our take
Hugo Award winner Stranger in a Strange Land follows Valentine Michael Smith, a human raised by Martians who returns to Earth and challenges humankind through his unfamiliar beliefs, extraordinary powers, and ideas of grokking and water-sharing, with a 4.3-star rating from more than 11,900 Amazon reviewers. A strong match for readers drawn to classic science fiction about culture, belief, human identity, and transformative outsider perspectives.
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About the book
Robert Heinlein's Hugo Award-winning all-time masterpiece, the brilliant novel that grew from a cult favorite to a bestseller to a science fiction classic.
Raised by Martians on Mars, Valentine Michael Smith is a human who has never seen another member of his species. Sent to Earth, he is a stranger who must learn what it is to be a man. But his own beliefs and his powers far exceed the limits of humankind, and as he teaches them about grokking and water-sharing, he also inspires a transformation that will alter Earth’s inhabitants forever...
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A strong match for readers drawn to hard science fiction, outbreak stories, genetic engineering, political tension, and near-future dystopian stakes.
Immunity Index
Dystopian · Genetic Engineering · Hard Sci-Fi
Our take
An Amazon Best of the Month pick, Immunity Index follows three young women in a near-future US shaped by food shortages, inequality, and authoritarian rule as they discover their shared genetic origins while a deadly virus spreads, with a 4.1-star rating from more than 100 Amazon reviewers. A strong match for readers drawn to hard science fiction, outbreak stories, genetic engineering, political tension, and near-future dystopian stakes.
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About the book
Sue Burke, author of Semiosis and Interference, gives readers a new near-future, hard sf novel. Immunity Index blends Orphan Black with Contagion in a terrifying outbreak scenario.
Bustle's 40 Best New Books May 2021
Amazon Best of the Month May 2021
In a US facing growing food shortages, stark inequality, and a growing fascist government, three perfectly normal young women are about to find out that they share a great deal in common.
Their creator, the gifted geneticist Peng, made them that way—before such things were outlawed.
Rumors of a virus make their way through an unprotected population on the verge of rebellion, only to have it turn deadly.
As the women fight to stay alive and help, Peng races to find a cure—and the cover up behind the virus.
At the Publisher's request, this title is being sold without Digital Rights Management Software (DRM) applied.
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Best for readers who like idea-driven hard science fiction with ringworld settings, far-future technology, space opera scale, and competing realities.
Lady of Mazes
Sci-Fi · Hard Sci-Fi · Space Opera
Our take
“hard SF at its best” by Stephen Baxter, Lady of Mazes follows Livia Kodaly as she becomes Teven Coronal’s only hope against human and superhuman invaders threatening its fragile ecologies and many human civilizations, with a 4.1-star rating from more than 100 Amazon reviewers. Best for readers who like idea-driven hard science fiction with ringworld settings, far-future technology, space opera scale, and competing realities.
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About the book
"This is hard SF at its best. . . Schroeder belongs to a dynasty that includes Benford, Vinge and Egan." —Stephen Baxter
Author and professional futurist Karl Schroeder, whose novels Ventus and Permanence have established him as a groundbreaking visionary in hard science fiction, extends his imagination into Larry Niven territory, returning to the same distant future in which Ventus was set, but employing a broader canvas, to tell the story of Teven Coronal, a ringworld with a huge multiplicity of human civilizations.
Brilliant but troubled Livia Kodaly is Teven's only hope against invaders both human and superhuman who would destroy its fragile ecologies and human diversity.
Filled with action, ideas, and intellectual energy, Lady of Mazes is the hard SF novel of the year.
"With Lady of Mazes, Schroeder gives us another novel of marvelous insight—brightest glimpses of where our technology of communication and computation may be taking us." —Vernor Vinge
"A complete original . . . it's the most thought-provoking and interesting work of hard SF that I've read in the past year, and it deserves to be recognized as belonging to the cutting edge of the new far future in SF." —Charles Stross
"An astonishing saga. One helluva read!" —Charles Harness
"Karl Schroeder has always had a knack for intelligent and provocative thought experiments, disguised as space opera. Now he ups the ante with a fascinating riff on consensual (and conflicting) realities. Lady of Mazes contains more cool ideas than Ventus and Permanence combined." —Peter Watts
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Best for readers who like Cold War thrillers, space-race tension, technical detail, and high-stakes missions in isolated settings.
The Apollo Murders
Mystery · Sci-Fi · Thriller · Space Exploration
Our take
“An exciting journey,” The Apollo Murders follows a top-secret Apollo 18 mission as flight controller Kaz Zemeckis uncovers a darker objective tied to a secret Soviet space station, with astronauts, spies, and political rivals colliding far beyond the reach of rescue, with a 4.4-star rating from more than 5,600 Amazon reviewers. Best for readers who like Cold War thrillers, space-race tension, technical detail, and high-stakes missions in isolated settings.
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About the book
From New York Times bestselling author and astronaut Chris Hadfield comes this exceptional thriller into the dark heart of the Cold War and the space race—soon to be a major TV series from Altitude and Sylvester Stallone’s Balboa Productions.
"An exciting journey" —Andy Weir, author of The Martian and Project Hail Mary
1973: a final, top-secret mission to the Moon. Three astronauts in a tiny spaceship, a quarter million miles from home. A quarter million miles from help.
NASA is about to launch Apollo 18. While the mission has been billed as a scientific one, flight controller Kazimieras "Kaz" Zemeckis knows there is a darker objective. Intelligence has discovered a secret Soviet space station spying on America, and Apollo 18 may be the only chance to stop it. But even as Kaz races to keep the NASA crew one step ahead of their Russian rivals, a deadly accident reveals that not everyone involved is quite who they were thought to be. With political stakes stretched to the breaking point, the White House and the Kremlin can only watch as their astronauts collide on the lunar surface, far beyond the reach of law or rescue.
Full of the fascinating technical detail that fans of The Martian loved, and reminiscent of the thrilling claustrophobia, twists, and tension of The Hunt for Red October, The Apollo Murders is a high-stakes thriller unlike any other. Chris Hadfield captures the fierce G-forces of launch, the frozen loneliness of space, and the fear of holding on to the outside of a spacecraft orbiting the Earth at 17,000 miles per hour as only someone who has experienced all of these things in real life can.
"Packed with cosmic action ... Featuring undercover spies, scheming Russians and psychopathic murderers, sometimes all at once, it teems with authoritative details." —The New York Times
“Nail-biting ... I couldn’t put it down.” —James Cameron, writer and director of Avatar and Titanic
“Not to be missed.” —Frederick Forsyth, author of The Day of the Jackal
“An explosive thriller by a writer who has actually been to space ... Strap in for the ride!” —Gregg Hurwitz, author of Orphan X
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A strong match for readers drawn to hard science fiction about first contact, space exploration, and life beyond Earth.
The Sunborn
Dystopian · Hard Sci-Fi
Our take
The Sunborn follows the mystery of marsmat, a complex life-form discovered beneath the surface of Mars, as the search for answers carries humanity beyond Pluto, with a 4.3-star rating from more than 60 Amazon reviewers. A strong match for readers drawn to hard science fiction about first contact, space exploration, and life beyond Earth.
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About the book
The multiple award-winning author of Timescape and Eater, Gregory Benford returns with a gripping new novel set in the same dynamic future as his wildly popular The Martian Race.
The first manned mission to Mars has been successful. However, there is a gathering mystery surrounding "marsmat"- the complex, anaerobic life-form that the expedition discovered inside a honeycomb of tunnels below the planet's surface. The search for the answers to humanity's ultimate questions about life in the universe will lead to the fringes of the solar system-to the dark and cold void beyond the planet Pluto.
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Best for readers who like queer sci-fi with marriage of convenience, class tension, political danger, and slow-burn romance.
The Mars House
LGBTQIA+ · Sci-Fi · Space Exploration
Our take
The Mars House follows January, an Earth refugee on Mars, and Aubrey Gale, a politician whose press-friendly marriage proposal turns into something far more complicated, with a 4.5-star rating from more than 900 Amazon reviewers. Best for readers who like queer sci-fi with marriage of convenience, class tension, political danger, and slow-burn romance.
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About the book
A compulsively readable queer sci-fi novel about a marriage of convenience between a Mars politician and an Earth refugee.
Named a Best Book of 2024 by The Washington Post * Amazon * Book Riot * LitHub * Paste Magazine * HuffPost
In the wake of an environmental catastrophe, January, once a principal in London's Royal Ballet, has become a refugee in Tharsis, the terraformed colony on Mars. There, January's life is dictated by his status as an Earthstronger-a person whose body is not adjusted to lower gravity and so poses a danger to those born on, or naturalized to, Mars. January's job choices, housing, and even transportation are dictated by this second-class status, and now a xenophobic politician named Aubrey Gale is running on a platform that would make it all worse: Gale wants all Earthstrongers to naturalize, a process that is always disabling and sometimes deadly.
When Gale chooses January for an on-the-spot press junket interview that goes horribly awry, January's life is thrown into chaos, but Gale's political fortunes are damaged, too. Gale proposes a solution to both their problems: a five year made-for-the-press marriage that would secure January's future without naturalization and ensure Gale's political success. But when January accepts the offer, he discovers that Gale is not at all like they appear in the press. They're kind, compassionate, and much more difficult to hate than January would prefer. As their romantic relationship develops, the political situation worsens, and January discovers Gale has an enemy, someone willing to destroy all of Tharsis to make them pay-and January may be the only person standing in the way.
Un-put-downably immersive and utterly timely, Natasha Pulley's new novel is a gripping story about privilege, strength, and life across class divisions, perfect for readers of Sarah Gailey and Tamsyn Muir.
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