Also, the World at War series as well, Set in the early years of WWII, aliens arrive.
My favorite time travel thing is, whenever someone
travels back in time, the Germans win WWII.
It doesn’t matter if they travelled back 2000 years,
or 60, the Germans win WWII.
And not only win, but take over the United States as well,
continuing a military occupation through today, without
ever having updated their uniforms.
Don’t ever travel back in time, unless you want Nazis
running in the streets.
My favorite sci fi storyline? Boy meets girl, boy loses girl . . . boy builds new girl out of spare parts.
Sorry. Very old joke.
Anyway, my real favorite subgenre is the good ol’ hard sci-fi juvie nuts ‘n’ bolts solar system exploration story, wherein the heroes triumph over the harsh vacuum (and possibly aliens and/or Nazis) through ingenuity, bravery, and sound principles of engineering.
I should have been born a boy in the Forties, emerging from the womb with a slide rule in my infant fist. Instead, here I am, a tomboy, vintage 1974, in an age where it is clear that nuclear rockets will not work, there are no canals on Mars, and I will never vacation on the Moon. sigh
bup, you actually reminded me of another alternate history favorite of mine, Philip K. Dick’s The Man in the High Castle. Oh, and I just reminded myself of Michael Bshop’s wonderful Dick homage/pastiche, Philip K. Dick is Dead, Alas–anyone read that?
(Am I the only one who thinks that aside from High Castle, Phil Dick’s talent is mostly concentrated in his short stories?)
I entirely agree with Nothamlet about the Iain M. Banks Culture novels, stylishly written and with a very clear view of how his universe works.
I also like the Night’s Dawn Trilogy by Peter F. Hamilton, big convoluted story about living peoples’ battle against the dead, who are enabled to return from the beyond by taking over people’s bodies. Again the authour has a really good idea of how his universe works, and does well to keep so many different stories running at the same time, without you losing the plot. I also like the fact that he has humanity split into Edenists with biotechnology super-developed, and Adamists with their neural nanonics and machine based technologies.
I, too, enjoy post-apocalyptic stories. I found “The Wild Shore” by Kim Stanley Robinson to be very good. It’s 50 years after the war, and the U.S. appears to be the only one who got whacked. There are Japanese patrols that wreck any project that smacks of technology.
I also like reading women writers on the same subject. Sherri Tepper’s “The Gate To Women’s Country” and Pam Sargent’s “The Shore Of Women” are very good. If you want to read about a world of women, where men are good for only one thing, then Sargent’s book will do the job.
Philip Dick’s The Unteleported Man – sadly out of print. A company on Earth has established a colony on another planet but the Gate only goes one way. But people from Earth keep going there because of what they see on TV (data apparently goes two ways). Then, someone figures out that the data is fake (fake applause on the cheering crowds). That is just chapter one, and then things get interesting…
“The Man Who Murdered Mohammed” – I forget the Author’s name. A scientist comes home to find his girl making out with another guy. Solution? Well, build a time machine and go back and kill her parents, of course. Didn’t work? Well, keep trying!
One story whose title I have long since forgotten – Astronaut goes into space and dies slowly due to a malfunction (with a huge media blitz), causing nation to conquer space with a renewed vigor. Well, the spoiler is a little obvious – the narrator at the end, pondering if space travel would have done as well otherwise, swears he sees his old friend the astronaut pass him in Times Square and concludes the whole thing was propaganda.
I’ve heard Dune is good, though I’ve never read it. Unfortunately the Arabs did. Spare some change for gas? 
Most influencial book written this century.
Sturgeon’s More than Human was good. Just your basic team of mutants – I don’t recall a plot. It is an expanded version of “And Baby Makes Three” about a guy at a shrink’s working through some mental block – it has been a long time since I read those too.
Spinrad’s book (Iron ???)that is, inside of it, a book written by Hitler had he become a sci-fi writer in another universe. I couldn’t finish the whole thing, but the forward (or was it afterward) by a faux proffessor was memorable. I think this was also a send up of the racism aliens symbolize in many of the darker corners of the genre.
I liked Niven’s Inferno OK. If you don’t have time to read Dante’s and are a fan of sci-fi, it is a few laughs.
Thanks to Narile for mentioning Lord Kalvan of Otherwhen. I hope in some alternate universe, H. Beam Piper is alive and still turning out fascinating fiction. I would add to the list his Space Viking, a fun read of my youth about a man whose bride is killed on their wedding day and goes a-viking to the stars. In spite of the premise, it has a grittily real feel to it, and the lead character does indeed go through some significant changes.
Also his mention of the Lord D’Arcy series is right on the money. I might also suggest that the two Michael Kurland D’Arcy sequels “Ten Little Wizards” and “A Study in Sorcery” are worth looking up, as it seems to me that they continue Randall Garrett’s high standards.
Do alternate-reality and alternate-history storylines count as SF? I like 'em, but not sure if they’re sci-fi.
I also liked Dick’s Man in the High Castle. Also liked Turtledove’s Guns of the South, but I’m getting tired of Turtledove–his POV style of narration is wearying. Why can’t he just tell us what happened for once, instead of relying on a recurring character to tell us? And so many recurring characters–hard to keep track of!
snif Has no one but me heard of, or liked, Pat Murphy’s There And Back Again?