Just some of my favourites:

• The Forever War - Joe Haldeman: Basically the vastly better Starship Troopers. Just don’t read the sequel.

• Old Man’s War - John Scalzi: Very much feels like an modern update of The Forever War

• Cities in Flight - James Blish: I just love the bonker’s idea of whole cities declaring their independence from Earth and just buggering off into space

• Ubik - Philip K. Dick: Hard to pick a favourite Dick, but this one just has all the mindfuckery and weirdness of that particular author in a perfect blend

The Expanse series has done it for me. Best books I’ve read in a long time.

I really enjoyed Project Hail Mary.

• Three Body Problem (and sequels, especially The Dark Forest:) it’s good scifi, though I worry that a lot of people missed the message.
• Consider Phlebas/Use Of Weapons: tragic space opera is my favorite kind.
• Gideon The Ninth: sci-fantasy popcorn with a sass-mouthed narrator.
• Providence: Fresh take on ubiquitous scifi tropes, and I’m a fan of Max Barry’s punchy writing style.

Jean le Flambeur series by Hannu Rajaniemi, probably better know by the first book of the series: Quantum Thief.

The world building is AMAZING. The author has a PhD in mathematical physics and the world is a far future extrapolation of what human societies could become. The “sufficiently advanced technology is indistinguishable from magic” kind of future without blatant contradictions with what could be possible by current science. It’s not a utopia or a dystopia, it’s “just” a world with multiple societies with their own lifestyles, ideals and problems. The other notable thing is that reading is a bit of a puzzle. You can understand the story without understanding every term and that’s essential because the workings of the world are obvious and mundane for the chracters and they do not go out of their way to explain them just for the benefit of the reader. But for me that is a big part of the charm to be tossed in a very foreign culture to figure out it all by yourself. Also since the author is originally from Finland (the book is still originally written in English) there are people who mostly chill in the Oort cloud in zero gravity saunas and making snow sculptures.

“Creatures of Light and Darkness”, and “Lord of Light” by Roger Zelazny - I love the blending of mythology and science fiction.

“Dune” though it hasn’t aged well in terms of the science of genetics.

“Cyteen” by C.J. Cherryh

“Starship Trooper” and “The Moon is a Harsh Mistress” both are peak Heinlein.

For me it is Foundation series because I like it’s themes and how they are presented, I really like some characters like Mule and Hari Seldon and it is very interesting to read.

I really enjoyed the ‘Foundation’ series by Isaac Asimov. ‘Rendezvous with Rama’ by Arthur C. Clarke is a great one as well.

I’m currently reading The Left Hand of Darkness, and so far enjoying it a lot.

My favourites are (still) HitchHikersGGTG and Good Omens. I just adore that writing style, I guess.

So many good recommendations! I’d like to add Ernest Cline’s ‘Ready Player One’ which I thoroughly enjoyed. Look into it if you are looking for a fun quick read and are somewhat interested in computer games and/or role playing.

For all suggested titles I can only recommend to read the books first. The movies are just a pale imitation and are lacking so much! Especially The Expanse but also the above mentioned Ready Player One are to be read IMHO.

infinite worlds of maybe by lester del rey. protagonist goes on a journey through alternate worlds in search of his father.

trick is the other worlds stability depends on their probability of occurring in reality. the less likely to occur, the greater chance it will disappear.

i think it was published in the 50s and possibly out of print.

I haven’t read Quantum Magician but certainly agreed on the Three Body Problem and Children of Time. Fantastic books.

Some others I really like:

• This Is How You Lose the Time War - short, poetic. Love it.
• Red Mars trilogy and really anything by Kim Stanley Robinson. Oh also in particular The Years of Rice and Salt
• Diaspora by Greg Egan and also much of his other stuff
• Player of Games and Use of Weapons from Ian Banks’ Culture series. Haven’t read all of them yet.
• Ancillary Justice

I’m a big fan of world building and well fleshed out settings and characters. I love getting lost in descriptive and unique imagery.

• Hyperion by Dan Simmons - feels like such a lived-in universe, some interesting tales, and a horrifying antagonist in the Shrike.
• Neuromancer by William Gibson - cyberpunk ahead of its time, great story, incredible atmosphere.

“The Dispossessed” by Ursula K. Le Guin is maybe the best political sci-fi book I’ve ever read. Cory Doctorow’s “Walkaway” is also quite good and feels a bit like its spiritual successor.