Much ink has been expended on science fiction: what actually is science fiction, what are the classics, is the Golden Age a fixed chronological period or personal experience? What is the sense of wonder, who belongs in the new wave, who were cyberpunks? What are the ten best stories, novels, authors, movies etc., and how does the list change?
But for both old or new science fiction, perhaps the unifying and defining aspect is that the questions are the same.
* Given the length of this post, please consult the ISFDB for cover information, or request additional information in the comments section.
What does it mean to be human,
What about the promises,
will we have jet packs, ray guns,
How will technology change us?
What kind of society will
What is intelligence?
Is there other life in the universe?
Will they be friends
What if the past had been different,
What about the near future, the far future?
What about the earth, the environment?
What is the universe like and will we ever explore it?
Will it be scary?
Is there a directing intelligence(s)?
How will human life end,