Science Fiction (SF) can be a difficult genre to define. English Professor Emeritus and SF author James Gunn probably said it best, “Science fiction is the literature of change.”
SF can be differentiated from Fantasy by its reliance on rationality and reason. The Fantasy author asks the reader to suspend disbelief, while the SF author persuades the reader to understand.
Hard SF, then, is the sub-genre that is the most rational, the most reasonable.
It gets its name from the so-called hard sciences which operate via the scientific method, e.g., physics, chemistry, biology, astronomy, geology. Hard SF is often written by real-life scientists/engineers and often features scientist/astronaut/engineer protagonists.
Furthermore, hard SF is often didactic; it tries to teach the reader some real-life science/engineering.
Here, rather than a strict numerical ranking, I group hard SF novels into several main categories, based on what type of science readers might learn: physics, astronomy/astronautics, math/computer science, climate science and biology/genetic engineering. The novels listed tend to skew towards more recent works because hard SF novels can become out-of-date as science progresses.
It should be noted, each author was limited to only one entry in the list below; often, an author has written several hard SF novels that could qualify as ‘best.’
Best Astronomy / Astronautics Hard SF Books
I believe the second-best hard SF novel of all time is Contact by astrophysicist Carl Sagan (1985).
There’s a lot of interesting astronomy here including some nuts and bolts of radio astronomy. Sagan also does a good job circumventing the speed-of-light speed limit of the universe via wormholes. (You may be familiar with the story because of the 1997 movie with the same name.)
In the novel, an astronomer discovers a mysterious signal seemingly from outer space. After additional study, scientists realize it’s a message from extraterrestrial intelligence(s) and contains the blueprints for some kind of transportation device. Earthlings build the machine, but several dramatic events ensue.
Personally, I love the story of the brilliant, plucky female scientist who perseveres against all odds and succeeds in making one of the greatest discoveries in human history. Eleanor “Ellie” Arroway is a great female role model, very much in keeping with the current zeitgeist.
Old Man’s War by John Scalzi (2005) is the first novel in his Old Man’s War series.
While some consider this one of the best military SF novels, it has a lot of fun hard SF ideas including nanotechnology, the faster-than-light skip drive, neural implants, space elevators, genetically engineered bodies and consciousness transfers from old to new bodies–not to mention extraterrestrial lifeforms.
Scalzi does a great job putting this book together. From the first short paragraph, “I did two things on my seventy-fifth birthday. I visited my wife’s grave. Then I joined the army.” we have empathy for the main character and are intrigued. Scalzi utilizes a war in outer space to explore concepts of mortality, individuality, and what if means to be human.
Blindsight (2008) by Peter Watts follows a group of astronauts investigating a trans-Neptunian Kuiper belt comet which is transmitting a radio signal.
It addresses first contact, artificial intelligence, consciousness, identity, game theory, and evolution/biology. The title comes from the condition in which vision is non-function in the conscious mind but remains functional to non-conscious action. There are several point-of-view characters, but the main one is Siri Keeton, the narrator, who can read other people’s intentions via cybernetics. The astronauts explore the object and make various discoveries.
Watts continues the Firefall series in Echopraxia (2014).
The Martian by computer scientist Andy Weir (2011) is a first-class hard SF novel. (Of course, it was a successful film in 2015.)
The plot involves a 2035 NASA mission to Mars that goes horribly wrong. One astronaut, Mark Watney, is accidentally left behind when the rest evacuate after a disaster. The Martian, then, is the story of Watney’s mission to survive.
The book shows many realistic elements of engineering, including repairing and repurposing equipment for energy, life-support, and communications. It also includes astronautical concepts such as orbital mechanics, slingshot trajectories, and gravity assists. Ultimately, though, it’s a close examination of a human being’s ingenuity and perseverance.
Weir’s 2017 novel Artemis, also has hard SF-worthy details, this time about the moon.
Seveneves by futurist Neal Stephenson (2015) is a sweeping epic covering the destruction of Earth and its terra-re-forming over thousands of years.
This novel has a lot of astronomy, astronautics, and also biology as humans rely strongly on genetic engineering. The genesis of this novel is the mysterious destruction of the moon, initially into seven pieces (a nod to the title).
These seven pieces form a ‘white sky’ blanketing the Earth in a hard rain of bolides, which boils away the atmosphere and destroys the biosphere. In part one, with two years to prepare, astronauts utilize the International Space Station along with temporary spaceships to evacuate as many people as possible.
Part two begins with the hard rain and thousands of evacuated humans trying to survive in Earth orbit. Stephenson’s description of Earth’s destruction is harrowing. In Part three, five thousand years have passed, and there are billions of humans living in space habitats, all descended via advanced genetics from seven women, or eves. Their attempts to terraform and immigrate back to Earth are this section’s drama.
Stephenson has written several SF novels which are enjoyable, including Cryptonomicon, almost on the Math list below.
Best Math / Computer Science Hard SF Books
Godplayers by Damien Broderick (2005) is a complex hard SF novel worth rereading. Broderick makes use of physicist Max Tegmark’s fascinating mathematical universe hypothesis; namely, our physical world is an abstract mathematical structure. He covers additional nonfiction information, including reading suggestions in his Afterword.
As if all those hard SF ideas weren’t enough, the story and characters in Godplayers are very entertaining. Australian medical student/cattle herder August Seebeck arrives home to find his great-aunt visited by disappearing corpses in the bath every Saturday night. August stakes out the tub, shockingly finds his aunt is correct and soon gets pulled into the Contest of Worlds along with his hitherto-unknown superhero siblings. It’s a battle between good and evil set in multiple universes.
Like I said, great fun! Enthusiasts can read more in Broderick’s 2006 hard SF sequel K-Machines.
In Rainbows End by Vernor Vinge (2006), the author addresses augmented reality and belief circles.
This is a prescient hard SF novel, in which people see only what they want to see and interact only with people of compatible mindsets. Security versus safety is also an important and timely theme of the novel.
Vinge does a great job capturing a kind of future-shock, i.e., technology-shock, relevant to real-life 2019. It’s also a very well-written and entertaining novel. Vinge introduces us to his world via Robert Gu, an older man who’s recently been cured of Alzheimer’s and has to integrate into the high-tech society.
Robert learns about this new world, and the reader learns right along with him. Soon, Robert gets embroiled in, among other things, sentient(?) avatars and a mind-control plot.
WWW: Wake by Robert J. Sawyer (2009) is about the emergence of an intelligence on the world-wide-web (WWW), from the perspective of a blind fifteen-year-old girl. It’s the first book in his WWW Trilogy.
There are a lot of hard SF ideas at work here including, cellular automata, packet loss, Zipf’s law, signal processor/computer-brain interface. This novel is thematically profound and has a very empathetic characterization of Caitlin Decter.
In brief, she receives some new tech, designed to help her see the physical world. But when she is able to see the internet, she detects mysterious information, and eventually, discovers the emerging webmind. Here, Sawyer explores the origin of consciousness at length via Caitlin.
Incidentally, I almost picked Sawyer’s novel Flashforward (1999), set at Higgs-boson-searching CERN, for this list. Hard SF physics fans should check it out, as well.
Nexus by computer scientist Ramez Naam (2012) is about nanotechnology, and programming and networking human minds. It reads like a thriller with very engaging characterizations of the main characters (e.g., law enforcement officer Samantha Cataranes, inventor Kaden Lane) and dramatic plotting.
Naam presents thought-provoking ideas along the lines of can we ever really contain technology once it’s been developed? And will humans use advanced tech for good or for evil? Or both?
Like a good didact, Naam appends a nonfiction section, “>>DEEPER,” explaining the science of Nexus, specifically, technology that allows people to communicate mind-to-mind.
The trilogy continues in Crux (2013) and Apex (2015).
Memories with Maya (2013) by technology expert Clyde DeSouza, is set in near-future Mumbai. It explores transhumanism, virtual reality, augmented reality, artificial intelligence.
The main character of the novel is really the Wizer technology, an augmented-reality visor driven by artificial intelligence. The human characters include DJ/hacker Dan and his girlfriend Maya, Maya’s brother Krish. Adventures ensue as Krish and Dan and friends develop the Wizer technology.
Among other things, there are some explicit virtual sex scenes between Dan and Maya. The novel definitely raises questions of what’s in store for the human race.
Best Climate Science Hard SF Books – this is also called cli-fi
Between the Strokes of Night (1985) by Charles Sheffield includes climate change and biological investigations of metabolism and brain function. It takes place during two different eras: 2010 and the far future of 29,000 AD.
In Sheffield’s 2010 world, global warming has already had a significant impact on Earth, including extensive crop failures. Space arcologies are built as a result, and warfare breaks out on the surface. Human survivors turn their attention to space.
In part two, almost 30,000 years later, Earthlings have colonized a planet in the Eta Cassiopeiae system. One of these, Peron, comes in contact with some of the original characters who have survived using S-Space, a method to slow consciousness to 1/2000th the normal rate. Peron and his colleagues continue their experiments in slowing consciousness until the end of the universe.
Sheffield has several hard SF novels readers would enjoy.
Heavy Weather (1994) by Bruce Sterling is one of the few ‘cli-fi’ novels that actually has meteorologists as protagonists.
Set in 2031, Sterling does a great job with world-building utilizing many interesting hard SF topics such as climate change, antibiotic-resistant disease, and monetary system challenges. The novel’s plot primarily concerns climate change and extreme weather.
A group of scientists and computer experts, storm chasers, ‘hack‘ weather, risking life, and limb in pursuit of scientific knowledge. More specifically, the Storm Troupe, led by scientist Jerry Mulcahey, seeks the upcoming catastrophic ‘F-6’ super-tornado—although whether they’ll survive when they do is anyone’s guess. Dramatic!
Forty Signs of Rain (2004) by Kim Stanley Robinson is an outstanding example of climate fiction or cli-fi. Together with Fifty Degrees Below (2005), and Sixty Days and Counting (2007), Robinson’s Science in the Capital trilogy is hard science at its best, showing scientists navigating the politics of the National Science Foundation, and, well politics.
Robinson has written several novels in the climate fiction sub-genre, e.g. New York 2140 (2017), but this is the most ‘hard’ in that the main characters are scientists. I almost picked his Red Mars (1992) for inclusion in the astronomy/astronautics section. The whole Mars trilogy (Red Mars, Green Mars, Blue Mars) is terrific.
Flood (2008) by Stephen Baxter describes a near-future Earth in which seabed fragmentation leading to extensive flooding.
Baxter was inspired by possible subterranean oceans within Earth’s mantle. Baxter’s scenario actually exceeds all predicted climate change. In this novel, beginning in 2016 and covering thirty-plus decades, the flood itself is basically the main character, as all humans have to deal with it. Eventually, human civilization is destroyed by the rising oceans
Baxter published a sequel to this, Ark, in 2009. He has several novels that might have ended up on this list. In particular, his Long Earth series ( co-authored with Terry Pratchett) is lovely.
Since a portion of The Quiet War (2008) by Paul McAuley occurs on Earth, and a portion in solar system colonies, this novel might be considered an unusual choice for hard climate SF.
However, this is one of the few novels that tries to fix our planet’s climate change problems. It is set in the twenty-third century, and much of it features the terraforming of Earth after an ecological catastrophe. The author does a good job explaining the biology of terraforming and his unique technology, such as the vacuum organisms with a kind of mechanical DNA.
There are five pov characters, but the two main ones are Macy Minnot, an environmental reclamation specialist, and Professor Doctor Sri Hong-Owen, a scientist; both of these women are good female role models. This is an enjoyable hard SF novel.
A sequel, Gardens of the Sun, was published in 2009.
Best Biology Hard SF Books
Published in 1932, Brave New World by Aldous Huxley, is by far the oldest novel on this list. Possibly you read it in high school?
Brave New World holds up surprisingly well as hard SF with its reproductive technology, sleep-learning, and psychological manipulation—all explained in its didactic opening. When the story starts the main protagonist Bernard Marx is a psychologist with an inferiority complex, unhappy with his life in the rigid highly-structured society.
This novel is considered one of the first dystopian novels so, not surprisingly, things do not go well for Bernard, or the protagonist introduced later, John. Reading the novel through the lens of the twenty-first century, Huxley’s society in which the populace enjoys drugs/entertainment, and can be controlled by inflicting pleasure and/or distractions, doesn’t seem far off.
Beggars in Spain (1993) by Nancy Kress is an admirable example of a hard SF novel featuring biology. This novel is acclaimed for its predictions of emerging technologies and of genetic engineering, bioethics, and competing social orders.
Fun fact: this novel is also considered a pillar of feminist SF. Kress is a master of characterization, world-building, and plotting. The central premise in the novel is the creation of the Sleepless, people who don’t sleep, via genetic engineering, and the consequences thereof.
As the story progresses, the massive advantages of the Sleepless result in a restructuring of human society and increasing stresses. The main story question is: what do the haves owe the have-nots in a world where technology is making workers obsolete?
Kress continues this marvelous Sleepless series with Beggars and Choosers (1994) and Beggars Ride (1996).
In Queen City Jazz (1994) by Kathleen Ann Goonan nanotechnology and genetic engineering have run amuck. Goonan is an innovator of nano- and biotechnology, together called bionan.
In Queen City Jazz, Goonan does a fabulous job creating an utterly unique world in which music and bionan result in profound changes in humans and their world. Specifically, Verity, a Shaker teenager trying to save her friend’s life, enters the ‘enlivened’ Cincinnati and gets enmeshed the pheromone-based chemical communications which have replaced electronic communications. Verity discovers the huge bio-engineered bees of the city have a special role for her.
Goonan continues her Nanotech Quartet with Mississippi Blues (1997), prequel Crescent City Rhapsody (2000), and Light Music (2002)–all wonderful.
Goonan’s lovely In War Times (2007) or This Shared Dream (2011) almost made this list in the physics section.
At first glance, World War Z (2006) by Max Brooks might seem an odd choice for a best of SF list. While a zombie war could be classified as horror, Brooks gets deep into the biological details of the plague, including patient zero, and medical and epidemiological procedures.
The format here is a little unusual as the story is told via a series of interviews, by a fictionalized Max Brooks, of survivors of the zombie plague. Brooks claims to have been inspired by The Good War: An Oral History of World Wat Two (1984) by Studs Terkel.
The 2013 movie of the same name has a very different tone and emphasis.
With a title like Children of Time (2015), you might expect this novel to concern time travel, but this one concerns biology, i.e., evolution.
Adrian Tchaikovsky does a remarkable job showing experimentation gone surprising in this tale of uplifting and sentient …spiders. He did extensive research, especially about speculative evolution, and it shows. The story covers epochs, has empathetic characters and dramatic plotting. It begins with human scientist Avarna Kern on a spaceship overlooking a planet which is being terraformed.
Drama ensues, and on the planet, spider Portia lays the first nanovirus-infected eggs—leading eventually to an entire spider society. There are two parallel storylines here: one is the evolution and uplift of the spiders, while the other is degeneration of humans. The plot is very unique.
Tchaikovsky continues the series with Children of Ruin, published in 2019.
Best Physics Hard SF Books
In my opinion, the best hard SF novel of all time is Timescape by Astrophysicist Gregory Benford (1980).
Benford does an excellent job realistically showing physicists at work. Furthermore, the characterizations and plotting are all excellent. In a nutshell, in the ecologically-ravaged 1998 United Kingdom, a group of University of Cambridge physicists sends a tachyon message warning of disastrous climate change to 1962 Earth. Tachyons are faster-than-light particles that are believed to travel backward in time. Meanwhile, in 1962 a group of physicists at the University of California discover strange signals in their spontaneous resonance experiment.
Suffice it to say, things do not go smoothly for these two groups of scientists, and in the end, the novel makes use of the Many Worlds Interpretation of quantum mechanics. This story is satisfying for its detailed character development, interpersonal drama, and SF plot points including climate change, time travel, and quantum mechanics.
By the way, all Benford’s works are worth reading for the hard SF fan.
Einstein’s Bridge (1997) by physicist John G. Cramer tells the story of physicists George Griffin, Roger Coulton, and novelist Alice Lang as they try to implement the Superconducting Super Collider (SSC) in Waxahachie Texas.
Cramer exhibits physics expertise in creating details of (what might have been) the operation of the SSC and the influence of politics on science. Since this is fiction, in addition, a mysterious new particle is detected, eventually revealing nonhuman sentients.
Cramer’s 1989 novel Twistor is also worth checking out for the hard SF fan.
In Diaspora (1997), Greg Egan goes so far as to make up some new theories of physics. For example, elementary particles are six-dimensional semi-point-like wormholes. Egan clearly understands real-world physics, making this novel a treat for hard SF fans.
The novel even has a helpful glossary, which explains Egan’s terms. The plot’s a little difficult to summarize; it centers on the nature and meaning of life, desire, and intelligence in a post-human context. For example, the novel begins with the birthing of the math-loving character Yatima, formed by the Konishi polis conceptory, rather than by parents.
Egan has several hard SF novels which could have ended up on this list.
Light (2002) by M. John Harrison is another hard SF novel featuring quantum physics. Light may be the most ‘literary’ entry on the list with a focus on sex and gender and a dark tone.
This haunting, mind-bending adventure takes place in two timelines. One timeline, contemporary London, features physicist and murderer Michael Kearney doing experiments. The second timeline, four hundred years in the future, features spaceship and pirate Seria Mau Genlicher and her virtual reality addict brother Ed Chianese. All three characters are linked by a mysterious evil entity.
The series continues in Harrison’s Nova Swing (2006).
Superposition (2015) by David Walton is an example of the hard SF subgenre I call quantum fiction.
The physics ideas of Superposition are bleeding-edge hard SF at its best. Walton does a particularly good job elucidating the concepts of quantum physics. When a murdered colleague shows up at physicist Jacob Kelley’s door, he gets pulled into a multidimensional mystery that bends space and time. Told with a nonlinear chronology, part courtroom drama, as the true nature of the crime is revealed, Jacob must protect his family and world from the quantum murderer.
Walton continues the series with Supersymmetry (2015). He has other books which could have made this list. The Genius Plague (2017) almost made the biology section.
There you have it. Twenty-five awesome hard SF books. Happy reading!