Best Classic Science Fiction (Semifinal 2)

What is the very best sci-fi book (or series) written before 1975?  

If we can go without another global pandemic breaking out, the second semifinal round should go much more quickly than the first, and we'll be looking at the final round by in early April. And if there are sharknados or something next week, then I give up and this will likely be the only poll for all of 2020.

Let me just make ONE caveat. This poll is about BOOKS. It's about writing. If you loved watching Sting play a Harkonin brother, but otherwise find Herbert to be dry and way more white savior than you can stomach, then find another title.

I'm working on a series of Coronavirus/Covid-19 themed posts and I hope the first one (tomorrow) kind of makes it clear why we got knocked back out of the productive tree again and have had to start climbing our way back up. In the meantime, huge shout outs to my friend LeeAnn who is piggy-backing two families and change (it's me--I'm the change) of grocery shopping together and keeping me flush in Cheez Its Grooves Sharp White Cheddar flavor so that I can have a couple of creature comforts while I try to convince my creativity to put down "disaster mode" and come over here to do some writing. She is the hero of my village right now.

Oh and do remember that half the titles were already voted on (from your nominations) before you let me know how derelict I have been in my duty not to include your fave.

The actual poll is on the left hand side at the bottom, beneath the "About The Author" section. 

Mobile viewers will have to go aaaaaaall to the very bottom of their page and switch to "Webview" in order to access the poll.

IF YOU CANNOT SEE THE POLL- You are part of a small but non-zero group. The free polling app I use recently changed hands and there appear to be some growing pains.  The following link should work for you:  https://poll.fm/10526604

Everyone will get three (3) votes. 

There is no way to do ranked choice voting, so please consider that every vote beyond the first "dilutes" the power of your initial vote and use as few as you can stand to use.