Here is a post by Victor Milan at tor.com: Five Classic Works of SFF by Authors We Must Not Forget
Interestingly, I have read only one of these — Lord of Light by Zelazny. But I do think it’s a shame to stop at five when there are so many. Couldn’t Milan have at least gotten to ten? I figure I’ll help him out by providing a few more, which I’m listing below in the random order in which they occurred to me:
6. The Gaean trilogy by Varley. It’s practically a crime, how little attention Varley gets today. There may be no other author of his era who would better appeal to modern readers.
7. Ringworld by Niven. Niven pretty much founded the era of extraordinary SF settings, and did it better than practically anyone since. Also, Michael Whelan’s vision brought it to life for readers:
8. Dune. Obviously.
9. The Riddle-Master of Hed by McKillip. Hard to believe this was first published so long ago, but so it was. Modern readers are sooooo missing out if they do not grab up this trilogy.
10. The Last Unicorn by Beagle. Again, I’m amazed to find out how old that one is. But everyone still reads it, right? Or do modern readers miss out because they’re so swamped by the recent releases that are getting the current buzz? That would be a shame.
What else should obviously be included on a list of must-read classic or great SFF? If you have a moment, please drop one book published before, say, 1990, in the comments.