It's been a while, some of these I wrote years ago.
The descriptions are inevitably somewhat *spoilerific*. But I won't mention all the major plot reveals and outcomes.
James P. Hogan: Code of the Lifemaker (1983) & Immortality Option (1995)
I bought these two randomly off a flea market.
The prologue tells how an automatic interplanetary robot explorer/factory system fails as the alien star system turns nova. After countless millennia, the crazed probe crashes on a moon of another system and the robots begin to evolve into self-conscious lifeforms. This results in a medieval robot world based on a non-carbon ecosystem, with some properties more advanced than Earth science could achieve.
On future Earth, an expedition is launched for Mars, revealed in process to be headed to Titan, but no-one gives a really good reason for the change of plans. Could it be...?
The real main character is one Zambendorf, a very public person who made a career by claiming he has psychic powers. The arguments for and against parapsychology are rooted around the time of the novel's writing, reminding of the Uri Geller phenomenon.
The initial parts of the novel reminded me of Alfred Bester's stories, but it is soon found out to be very different. In addition there's some weird soapboxing against solar power and other "green" or "leftist" mindsets.
The idea of the self-evolving robot life was interesting, whereas comedy takes center stage as the antics of the medieval robot scientists and religious fanatics are explored.
The sequel, written a decade afterwards, acts both as a direct sequel and a kind of prequel to the first book, detailing the events leading to the robot evolution. Topically, there's less of the robotic science-religion irreverence, and more attention is paid to intelligent entities living within computer networks, in essence "fixing" the absence of software AI's from the first novel.
Neither of the novels are especially good, age hasn't graced them and the plotting is convoluted. Although Zambendorf's parapsychology is made to some good use in both of the novels, at the same time it flattens the story to an anecdote about outwitting the opponent.
Apart from all the hijinks and comedy, Hogan has managed a relatively plausible first contact scenario without resorting to faster than light travel.
Larry Niven and Jerry Pournelle: The Mote in the God's Eye (1974)
Niven and Pournelle co-wrote this fairly brick-sized novel about humanity's first encounter with an alien race far in the future.
As a fun inversion, alien language isn't a problem as they learn English quickly enough. In contrast, the complexity of their language prevents it from being ever understood by humans. Come to think of it, something similar happened in Hogan's novels discussed above.
The alien race appears to have many resources and skills humans do not have. The question arises, as the puny humanity has invented faster than light jump travel long ago, why are the ostensibly more intelligent aliens stuck on their homeworld?
Apart from this central mystery, this sci-fi examines what precautions need to be taken in a first contact situation, what misunderstandings might take place and how could they be resolved.
Niven explores his style of alien races with ease, incorporating the geometric thinking that helped make Ringworld intriguing. For example, the logic of the hyperjump to the Mote system, and the reason why the Mote's can't do it in reverse, is satisfyingly spatial.
I'm less sure what Pournelle's contribution to the novel is, but the more muted naval military elements of the Human Empire feels less Niven. Consulting Wikipedia, the novel indeed takes place in Pournelle's universe. There's some of Niven's usual silliness and stereotypical characters, and the novel really doesn't rise above its plot, which was enjoyable enough.
The Mote in the God's Eye is rather modern sci-fi for something published in 1974. Perhaps because now the generic video game sci-fi universes resemble the one presented here.
Also, those parts of the Halo video game universe and plot, which are not taken from Niven's Ringworld, are largely derived from this book. Or Pournelle's universe, to be more precise.
Or it's just that sci-fi ideas in popular culture simply became stuck in the 1980s.
Vernor Vinge: A Fire upon the Deep (1992)
This has even been translated to Finnish ("Linnunradan ääret", 2001), but I've missed it entirely.
It turns out that from our local vantage point, we don't know that much about how universe works. Towards the center of the galaxy, machines work less effectively, spaceships move slower, even organic minds begin to lose their capacity. Moving outward, towards the galactic rim, faster than light travel is possible, technology works more fluidly and even minds are more capable.
A vast conglomerate of alien cultures mingle with each other there, communicating through an ultra-internet spanning the galaxy, or rather, the outer rim.
This creates a dynamic backdrop for stories that might not make much sense in our physically constrained universe. Conventional sci-fi empires in the slow zone have little expansion potential before they perish. Civilizations like the Earth's, have a hope of ascending through, but they might just as well become extinct.
Then, something wicked this way comes from the human outpost of Straumli, awakening even the interest of the Powers, entities transcended beyond the galactic rim. Shortly after the rapidly escalating catastrophe, a human refugee ship descends on a medieval world, with a pack-mind culture unaware of the rest of the galaxy.
What at first appears tiresomely post-modern and post-internet mish-mash of confusion, is eventually balanced with what is essentially a rollicking space opera, with twists and turns and reveals round every corner.
The story, problems and solutions are intertwined satisfyingly with the world concepts. The pack-mind alien race and the universe only really work in the written medium, otherwise I guess it would have been filmed already.
David Brin: The Postman (1985)
After a short nuclear winter, the United States is reduced to a scattered wasteland, Western-like territories with mountain men and outlaw gangs. Jeremiah Johnson is even name-dropped.
Gordon makes a living travelling about and performing little plays and leading entertainment events with singing and stories that remind people of times before the fall.
When Gordon finds a near-intact post courier's jeep, with a mail bag and a uniform, this sets wheels in motion. Due to the uniform, he gets a grand reception at a village of simpletons. Being a bit of an idealist, Gordon continues to work as a mail carrier in the name of the Restored United States. But does this play act become more real in the process? Are symbols really so strong?
The book is quite episodic, Gordon's role as a Postman leads him to various locales where people attempt to keep up civilization. Instead of staying as a picaresque, the story escalates and leads to larger themes.
The last portion of the book is like the end part of a sequel book was bolted on, with partly different characters and themes that were not developed in the beginning. Apart from this incongruity it does make fun reading.
Fred and Geoffrey Hoyle: Rockets in Ursa Major (1969)
Earth sent the rocket DSP-15 to "Ursa Major" thirty years ago, its crew in deep sleep. All such journeys apparently failed or fell silent, but now the DSP-15 has inexplicably returned.
This is an interesting setup, but then the action shifts too soon into high gear, forgoing the mystery. Soon all points to an alien intelligence, set to invade the Earth. No sooner a ship is sent to probe the outer reaches of the solar system, the attack is found to be already in process.
The book can be dismissed as a novelette for juvenile audiences, with the "Hullo, Dick, wait while I adjust the batteries of my chrono-temporal wrist terminal" type dialogue and heavy-handed description of gadgets in the future world, most of them having no bearing on the actual story.
However, the story has a nice example of the "dark forest" concept. There's a thriving galactic community of aliens, and a malevolent race only called the Yela, the Unseen Ones. They would destroy the Earth just because they know it exists. Pour hydrogen on the atmosphere, apply pressure, and voilà, life on Earth will be vaporized.
This alone is a thrilling concept, but there isn't much else going for Ursa Major. The space battles are fun, unpretentious bashing using rigged torpedoes and such. The inevitable table-turning solution is a little too bombastic and not too credible, but the story had to stop somewhere.
Arthur Clarke: Rendezvous with Rama (1973)
A well known and deservedly a classic, Rendezvous with Rama is a story of an interstellar object arriving to the solar system. When ʻOumuamua did the rounds around 2017, it spurred many comparisons with this novel.
As human race has spread out to habitate the solar system, it's not too much of a problem to divert one competent spaceship crew to the silent cylindrical mini-world dubbed as Rama. Landing on top of it, they discover a way in and thus begins the adventure for discovering the secrets of a dead, alien culture. Or is it so dead after all?
Possibly the best book on display here, I am somehow less eager to divulge its contents. Suffice to say it's a rare example of a science fiction novel where the initial mystery is not flattened through the story's conclusion. There are sequels, but they were made so much later I suspect they are not worth reading.
Isaac Asimov: Nemesis (1989)
A latter day Asimov I've somehow been able to avoid.
Using a half-realized FTL drive, a group of human settlers are able to reach Nemesis, a star system only couple of light years away. As the star has escaped detection, the shrewd commander of the colony has decided to keep it secret from Earthlings and the other solar system settlements.
Meanwhile, it is revealed Nemesis might eventually hit the solar system, with grave consequences for Earth... are the Earth politicians and their soon overpopulating melting pot, that much better?
Asimov weaves together a perhaps too many threads for comfort, as the human drama, near-telepathic inference talent of one Marlene, and the mystery of the Plague on the settler world Erythro take the center stage. But "comfort food" it essentially is, mystery piling on mystery until it is all unraveled.
Asimov makes a point of saying the story is not part of the Foundation and Robots series, which is just as well as I didn't include it in my massive Asimov through-read...
...however, the statement might be something of a red herring, as the story isn't that contradictory with the larger Asimov tapestry. He never said it wasn't part of the same universe! The very end and the epilogue makes the connection rather blatant, hinting at the Earth/Spacer split, future events and possible makeup of the early colonies. This may include, among other things, the potential origin for the trans-human Solaria and eventual mind-controlling factions in the Foundation novels.