I don't think anything should be "required" to get into SF. Let people enjoy what they enjoy - there's no "you're not a proper fan until you've read...." exam.

For ANY genre! Let people read what they want! FFS

Only one of these two writers could write believable human characters. Their ideas are what propelled their narratives. But required reading? Nah. That's so much elitist bollocks.

I liked all three when I read them in the 80s and 90s, but some of Heinlein made me pretty uncomfortable even then. I don't really believe in "required reading" for enjoyment, but if there were a required author it would be Le Guin.

I think we have to be careful with required - even Le Guin makes some mistakes and has highlighted them eg Left Hand of Darkness - so when we are talking to new readers to a genre I tend to think we can go a bit more modern

I haven't read Left Hand in like 20 years... Is there a problem with it? I don't recall.

Le Guin felt she’d not quite nailed the gender dynamics of the aliens quite right with the way she now treat change of genders

She even apologised for some bits.

Reading through Earthsea, one can see how her viewpoint both refines and expands over time, from story to story, instead of becoming more entrenched in itself with age.

even so, whenever I do see people discovering her it's almost always either Earthsea or Left Hand. For all their flaws, they can still capture new readers.

They can but I’d be interested if they were adult or teenage? a Wizard is a lovely read but very different to how ya fiction works now - Tombs though I think could…

Always Clarke for me, but things have moved on. As someone once said, the Golden Era of sf was when you were thirteen.