The best real science fiction novels—meaning hard sci-fi dealing with space, technology, alien cultures, and other worlds—especially focused on detailed world/species creation.
Excludes fantasy, psychological, dystopian, horror, time travel, political, activist, and arty stuff (1984, the Time Machine, 2001 Space Odyssey, Foundation).
Ringworld, Larry Niven (1970)
A quartet of adventurers set off to explore an artifact of incredible proportions; a ring of matter ninety million miles in radius. The best world building ever—the Ringworld itself, technology, and the various species (Puppeteers, Protectors, Kzin). The series starts off fantastic, but drags a bit as it goes.
Fleet of Worlds, Larry Niven (2007)
A prequel series to the Ringworld series, which focuses on the Puppeteer species. Puppeteers, being the most cautious race in Known Space, also end up with the most advanced tech, because other species blow themselves up along the way—tortoise vs the hare. Niven species design makes sense. The series starts off great, but later lags.
Protector, Larry Niven (1973)
Features the best ultra high-IQ alien species ever; Protectors. At this level of intelligence (IQ 1200) subjectivity drops away, and they calculate probabilities many moves out to view knowable outcomes. War between them gets interesting as they already see where all possible moves likely lead. Set in Known Space (Ringworld and Fleet of Worlds), but stands well on its own.
Rendezvous With Rama, Arthur C. Clarke (1973)
An unknown object comes toward Earth and a space team is sent out to explore. Features the concept of a cylinder that spins to create gravity and a giant livable world inside. All time classic, if you don’t like Rama then you don’t like real sci-fi. There is a series, but it drags on.
Old Man's War, John Scalzi (2005)
The oldies get prolonged life and genetic enhancements, in exchange for being shipped off to interstellar space to kick alien ass. An incredible piece of military/alien sci-fi work—modern classic status. The second book Ghost Brigades is also great, and the following two The Last Colony, and Zoe’s Tale are good.
Speaker for the Dead, Orson Scott Card (1986)
Serious sci-fi, not to be confused with Ender’s Game which precedes it in the series. You think about how difficult it is for homo sapiens to comprehend other cultures in their own species, now think about how impossible it would be for them to comprehend other species! Also, I recall the following two, Xenocide, and Children of the Mind being fairly good.
Enderverse, Orson Scott Card (various)
The rest of the “Enderverse” novels are not terrible. They are just overshadowed by the exceptional Speaker for the Dead, and the popular Ender’s Game which became a goofy kid flick. The Formic War series is okay military sci-fi also featuring alien culture differences, and the Shadow Series has some okay political sci-fi maneuverings.
A World Out of Time, Larry Niven (1976)
Cryogenic guy (a “corpsicle”) awakens in a bizarre future society (“the State”) and in somebody else’s body, escapes in a small star ship, rounds a black hole projecting himself 3 million years into the future, then comes back to future Earth! Best far-future imagination ever. Technically this is part of The State series but it is not set in the gas ring world, and stands on its own.
The Integral Trees / The Smoke Ring, Larry Niven (1983 / 1987)
A world without a planet; trees floating around inside a gas ring which surrounds a neutron star. Features speciation; humans adapt to this new world across the centuries. But then recontact happens between them and “the State,” humans’ annoying totalitarian world government.
I, Robot, Isaac Asimov (1950)
A collection of interlinked stories about robots. Features Asimov’s “three laws of robotics” concept, which is the best part. The robots are overall helpful, but occasionally get off the leash; go crazy or otherwise cause trouble. Different from the movie which borrows concepts here and there.
The Naked Sun, Isaac Asimov (1956)
A sci-fi detective murder mystery set on the distant planet of Solaria—who done it, robot or human? Features interesting world building; a planet with a strange local culture where a small number of human hermits control vast technological resources and are massively outnumbered by their robot servants. The Caves of Steel is also a murder mystery, but set on future Earth where people live inside massive metal dome-covered cities.
The Forever War, Joe Haldeman (1974)
Military sci-fi; a war fought in a time dilation battle field, which lasts a thousand years. Illustrates how weird interstellar war would get due to the pesky laws of space/time. If you survive, and come back “home,” you are hundreds of years out of your time. There is a series, but I never got to it.
The Moon Is A Harsh Mistress, Robert Heinlein (1966)
In 2075 the “Loonies” (moon residents) revolt and decide to kick their Earthen masters’ ass. Features an exploration of their peculiar moon-based culture, an interesting self-aware computer named Mike, and interplanetary war tactics. A real classic.
Childhood's End, Arthur C. Clarke (1953)
Overlords who are superior to humans appear over Earth’s cities; seemingly benevolent they guide humanity down a new path based on their own agenda. This gets a bit into utopian/dystopian arty sci-fi, but it’s fantastic.
Gateway, Frederik Pohl (1977)
A space station is found, built by a long-gone alien species. The station’s ships have pre-programmed paths to unknown destinations. Humans start playing with technology they don’t fully understand—will a chosen path make you wealthy due to an incredible discovery, or drop you into a black hole? The first novel in the Heechee Saga.
The End of Eternity, Isaac Asimov (1955)
“Eternals” monitor and tweak the timeline, but one of the Eternals goes rouge, and makes a big time-mess. Time manipulation stories don’t make sense, but this was written before the topic was burnt out, and is quite good.
The Mote in God's Eye, Larry Niven, Jerry Pournelle (1974)
In the year 3016 humans make first contact with “the Moties,” seemingly friendly furry creatures living around a remote star surrounded by a dust cloud (“the mote”), and then all goes horribly wrong.
World of Ptavvs, Larry Niven (1966)
A mysterious statue, 1.5 billion years old, is found at the bottom of the ocean—a stasis field holds captive a telepathic alien inside. Features psychic warfare, and ultra powerful alien artifacts. A bit dated but interesting and fun.
Footfall, Larry Niven (1985)
Straight-forward assault on Earth—elephant-like alien invaders with a herd mentality descend and blast human installations with asteroids. Conquerors demand surrender, or death to humanity. A bit dated yet fun.
Bowl of Heaven / Shipstar, Larry Niven, Gregory Benford (2012 / 2014)
While crossing interstellar space humans find an immense bowl-shaped structure built around a star, and explore the mystery of its origins. The bowl is inhabited, and some of the story is told from the perspective of the aliens observing primate behavior. It’s like Ringworld and Rama, but not as good. Included here for its world building.
The Memory of Earth, Orson Scott Card (1992)
A technology known as the Oversoul watches the human settled planet Harmony. Features mind-control technology to “protect” humans (some utopianism here), but the tech starts breaking down with age. Later in the series neat tech artifacts are discovered. The Oversoul tech has some God-like religious parallels (loosely based on the Book of Mormon). It’s not bad. The first novel in the Homecoming Saga.
Starship Troopers, Robert Heinlein (1959)
This is a serious work, nothing like the goofy movie. It popularized the idea of powered battle armor, which is used in fighting the bugs. Features an interesting civilized and orderly society, made possible by consistent harsh punishments (thereby rarely needed).
DIDN’T MAKE THE LIST
Foundation—unbearable space politics, see also Dune. Stranger in a Strange Land—fantastic but ideology, religious cults, and goofy Martians with impossible mind powers. War of the Worlds—again with the goofy Martian stuff. 2001 a Space Odyssey—a classic but too arty for this list. Do Androids Dream of Electric Sheep and 1984 and Brave New World—great, but more dystopian than sci-fi exploration. The Martian—fine, but reality-based, not really sci-fi.
What happened to sci-fi writing? Incredible ideas came out of the 60/70s, and then the imagination machine steadily slowed. Always looking for new works, Old Man’s War (2005) was the last one I considered a classic.