Our rankings are cleverly generated from the algorithmic analysis of thousands of customer reviews about products, brands, merchant's customer service levels, popularity trends, and more. The rankings reflect our opinion and should be a good starting point for shopping. As an Amazon Associate we may earn from qualifying purchases. We may receive a commission from purchases made through links on our site, which will help us continue to provide you with value.
Best Choice Hard-SF.com 
The Urania Project: Hard Science Fiction Best Value 
The Pull: A Hard Science Fiction Quest Beyond the Blind Spot (Cosmic Thresholds) 
The Somatic Bridge: Gripping New Hard Sci-Fi Adventure. (Expansion Book 1) 
Gravity's End: A Hard Sci-fi Novel in Space 
Keepsake: A Meridian Cut Science Fiction Story (Worlds Made Livable) 
Terminator: Hard Science Fiction on a World That Never Turns (Cosmic Thresholds) 
The Receiver: A Hard Sci-Fi First Contact Techno-Thriller Hard-SF.com Mars Genesis: The Last Voyage: Hard Science Fiction Exodus (The Exodus Trilogy Book 1) Starquake: Hard Science Fiction at the Edge of Survival (Cosmic Thresholds) Contact: Echoes in the Dark: Hard Science Fiction Pygmalion Media Generations: A Science Fiction Mystery Thriller The Sower of Stars: A Side Story of A Brief History of the Universe (A Brief History of the Sci-Fi Universe) Sci Fi Books Akashon Prime: A Hard Science Fiction Action Adventure (The Origin Series Book 2) The Object: Hard Science Fiction Xenophile Press Oblivion Threshold: A Military Science Fiction Space Opera Epic (The Oblivion Saga Book 1) Edenroot Press Deep Space Expedition: A Hard Science Fiction Survival Mission (The Threshold Protocol Book 1) Hard-SF.com The Enceladus Mission: Hard Science Fiction (Ice Moon Book 1) Bastion (Toy Starship Book 4) Broken Earth Rogue (Book 1 of The Rogue Series) Exodus Blue: A Posthumanism Hard Science Fiction Novel with AI and Mystery (The Colour of Blood Book 1) Menlo Park Press Perun's Hammer: A Novel Stephen Arseneault AMP Messenger: (Book 1) Uphill Downhill Press, LLC Wine Dark Deep: A Hard Science Fiction Space Opera - Book One: 1 A7L Thrilling Books Limited The Genesis Signal: Science Fiction Thriller The Darkness Between the Stars (First Contact) The Returner: A Post-Apocalyptic Military Science Fiction LitRPG (The Returner Book 1) Edge of Night: A Hard Science Fiction First Contact Thriller — Black Hole Survival, Ancient Alien Technology, and One Pi Das Echo: Hard Science Fiction (German Edition) Hard-SF.com Mars Nation 1: Hard Science Fiction (Mars Trilogy) Red Foundations Publishing Red Foundations: A Hard Science Fiction Epic (Red Foundations Universe Book 1) The Wanderer: Hard Science Fiction from the Darkest Ocean (Cosmic Thresholds) Hard-SF.com The Lost Planet: Hard Science Fiction (The Marchenko Logfiles Book 6) A7L Thrilling Books Limited Das Orakel: Hard Science Fiction (Erstkontakt) (German Edition) Exemplar: Hard Science Fiction: The Autonomous Sequence (Book 1) Hard-SF.com The Disturbance: Hard Science Fiction Edenroot Press The Quantum Drift: A Hard Science Fiction First Contact Thriller (The Threshold Protocol Book 2) Superposition: Der Beobachter-Kollaps: Hard Science Fiction Thriller (German Edition) Hard-SF.com The Torn Planet: Hard Science Fiction (The Marchenko Logfiles Book 1) The Wooden Pen Press Venusian Uprising - A Military Hard Science Fiction Epic (Aeon 14: The Sol Dissolution Book 1) The Wooden Pen Press Venusian Uprising - A Military Hard Science Fiction Epic (Aeon 14: The Sol Dissolution Book 1) Solan Publishing Journey Home (Standalone Sci-Fi Novels) Independently published Genesis: The Forgotten: (Hard Science Fiction) Futureword Publishing Blue SunRise: A Riveting Character-driven Hard Sci-fi Adventure (Blue Sun Space Opera Book 1) The Mars Anomaly: Hard Science Fiction The Daintree Protocol: A Hard Science Fiction Techno-Thriller Hard-SF.com The Tiny Planet: Hard Science Fiction (The Marchenko Logfiles Book 5) The Last Signal: A Hard Science Fiction Novel of First Contact and Lost Civilizations Hard-SF.com The Atacama Incident: Hard Science Fiction The Silent Colony: A Hard Science Fiction Novel of First Contact and Ancient Secrets The Silent Colony: A Hard Science Fiction Novel of First Contact and Ancient Secrets Amazon Original Stories Slow Time Between the Stars (The Far Reaches collection) Night Shade Books The Best of Greg Egan: 20 Stories of Hard Science Fiction Hard-SF.com The Luna Monolith: Hard Science Fiction (The Black Monolith Book 1) A. Nation Books Rogue (Book 2 Science Fiction Mystery): Catch Me If You Can (Blackhawk Files) scifi-thriller.com Reactor: Science Fiction Thriller Science Fiction Books Phantom 500: A Hard Science Fiction Space Opera Epic (The Origin Series Book 1) J Triptych Publishing Visitor: A Hard Sci Fi Thriller (Transcendence Book 1) Five and a Quarter: Hard Science Fiction Galactic Spacetime Publishing Time is not Enough: A Science Fiction Spy Thriller J Triptych Publishing Visitor: A Hard Sci Fi Thriller (Transcendence Book 1) Horizon Array: A Hard Science Fiction Survival Thriller Mirth Publishing Starship New Jersey Box Set: The Complete 10-Book SciFi Series Green Hill Publishing Homo Machina: A Post-Apocalyptic Hard Sci-fi Genetic Engineering Thriller Primordial Press Primordial Threat: A Hard Science Fiction Thriller (The Exodus Series Book 1) Hard-SF.com The Krill Enigma: Hard Science Fiction Endeavour (A Sleeping Gods Novel Book 1) Instrumental: Hard Science Fiction: The Autonomous Sequence (Book 2) Hard-SF.com The Luna Monolith 3: Hard Science Fiction (The Black Monolith) Hard-SF.com Andromeda: The Encounter: Hard Science Fiction (The Long Journey Book 1) Hard-SF.com The Triton Disaster: Hard Science Fiction (Solar System Series Book 4) The Earth Signal: A Hard Science Fiction story about magnetic fields, human consciousness and the potential destruction Cosmic Thresholds, Volume I: Three Hard Science Fiction Stories Hard-SF.com Andromeda: The Encounter: Hard Science Fiction (The Long Journey Book 1) Independently Published The Year's Top Hard Science Fiction Stories 2 Hard-SF.com Mars Nation 2: Hard Science Fiction (Mars Trilogy) AS1 Pole-Zero Publishing The Cold Heavens: A Hard Science Fiction Adventure (The Olympian Order: Sky-Pirates of Venus Book 1) Hard-SF.com The Portal: Hard Science Fiction (Portal to Xibalbá Book 1) Hard-SF.com The Hole: Hard Science Fiction (Solar System Series Book 1) Hard-SF.com The Shared Planet: Hard Science Fiction (The Marchenko Logfiles Book 3) A. Nation Books FOUND (Hard Science Fiction with Deep space exploration - Domino Book 4): The Lost Ones When the Pattern Breaks: A Sci-Fi Thriller (The Pattern Series Book 1) The Babb-L Incident: Silence is the Final Firewall: A Hard Science Fiction Thriller Primordial Press Freedom's Last Gasp: A Hard Science Fiction Thriller (The Exodus Series Book 2) The Wooden Pen Press Lyssa's Run - A Hard Science Fiction AI Adventure (Aeon 14: The Sentience Wars Book 2) The Architects of Time: A Hard Science Fiction Cosmic Mystery (The Paradox Archive) Hard-SF.com Proxima Trilogy: Part 1-3: Hard Science Fiction Independently published The Disturbance 2: The Answer: Hard Science Fiction Monolitix Press Uluru: The Price of the Stars - Book 1 Monolitix Press Uluru: The Price of the Stars - Book 1 Hard-SF.com Proxima Rising: Hard Science Fiction (Proxima Trilogy Book 1) Hard-SF.com The Titan Probe: Hard Science Fiction (Ice Moon Book 2) 18% Off HarperVoyager The End of Eternity: A Classic Hard Science Fiction Adventure of Love and Time Travel The Rift: A Science-Fiction Thriller Hard-SF.com Silent Sun: Hard Science Fiction (Solar System Series Book 2) Hard-SF.com The Luna Monolith 2: Hard Science Fiction (The Black Monolith) Hard-SF.com Return to Enceladus: Hard Science Fiction (Ice Moon Book 4) Hard-SF.com Mars Nation 3: Hard Science Fiction (Mars Trilogy) The Operation Northern Lights : a gripping sci-fi thriller (The Cleaners Book 1)