james_nicoll

I don't think I've read any Niven from that period, so I'll play it safe and just name Rosemary Kirstein and Donna Andrews. If we lowered the bar to "harder than Ringworld", I think I could add Kristine Smith (I finally completed my set of her books today).

There is no lowering of the bar. Niven in 1968 was not more rigorous than Niven in 1970 or Niven today.

Oh yeah, I second Kirstein.

(Bujold but it doesn't show. Reading through her father's credits I had the insight that LMB writes non-destructive military SF.)

Immediate thoughts: Elizabeth Moon, Lois McMaster Bujold, and CJ Cherryh

moon is mostly space opera.

If "hard SF" is defined as SF that respects the laws of physics, then Ursula Le Guin is the preeminent hard SF writer, and very few other authors even qualify. Not Niven, sorry. But he did write some very engaging Space Fantasy.

Isn't LeGuin the primary popularizer of the ansible?

Hm. Does Chris Moriarty count?

She was the first person I thought of. Also Linda Nagata. And Alison Sinclair's SF. And Joan Slonczewski.

I am sceptic, given the mining of Bose-Einstein condensates in shirtsleeve environments.

Considering that I found Ringworld boring (this after a B.S. in physics), take these with a grain of salt. Not all output of these authors, of course, is on the harder end of the sf continuum.

C.J. Cherryh
Pat Cadigan
Sarah Zettel / C.L. Anderson
Melissa Scott
Elizabeth Bear (Jenny Casey series, although I think Kristine Smith's series is better)

+1 on Kristine Smith

Could Diane Duane's magic count (So You Want to Be a Wizard)? You have to remember details like including air within a force field and not translocating into solid objects.

Melissa Scott is mostly fairly fast and lose with her science (although, Dreamships and Dreaming Metal would IMHO count), and I'm uncertain about Cherryh, but definitely Pat Cadigan - it's a darn shame she seems to have largely stopped writing.

For the first standard: Cherryh, Le Guin, Mary Shelley, Joan D. Vinge, Linda Nagata and Octavia Butler would all be able to easily step over a bar quite a bit higher than that (say, one set to early-Heinlein levels of hardness).

The second standard hits the slight snag that there are very few writers of any gender who would pass it, and my knowledge of female sf writers is too limited to produce any candidates at all.

Niven gets you psi, so not diamond hard by any means. At that point, the obvious choices (at least from my PoV) are:
Vonda N. McIntyre
Joan Vinge (excluding her Psion series)
Nancy Kress
Linda Nagata
Rosemary Kirstein

Catherine Asaro is a physicist but I don't know if she uses her background in her sf.

Off the top of my head, without even pausing to think:

Ursula Le Guin, all the Hainish universe novels and stories
Joan Slonczewski, A Door into Ocean
C. S. Friedman, In Conquest Born
C. J. Cherryh, Downbelow Station
Melissa Scott, Dreaming Metal/Dreamships
Laura Mixon, Burning the Ice
Octavia Butler, the entire Bloodchild collection
Sydney van Scyoc, the Darkchild trilogy
Vonda McIntyre, Superluminal
Kristin Landon, The Hidden Worlds trilogy
Elizabeth Bear, Undertow

Athena Andreadis

I'm not even slightly acquainted with some of the writers mentioned, nor do I know all that much about Science, but I've found Bujold impressively convincing on that score (as well as on several others).

Rereading the Vorkosigan series at the moment; Bujold writes hard science fiction you don't notice, as it's all hidden in plain view in the background.

Which is as it should be. Bujold was the first on mental list, possibly because I just read Cryoban on the strength of one of last week's threads.

But it strikes me that "as it should be" is highly chronologically dependent, and I'm not talking about the state of scientific or technological knowledge either. I think Niven is the canonical case in point; for 1968 he may have been doing hard sf, and one could even argue that Ringworld fills the bill too.

But would any of that stuff - assuming it could be published now - be considered hard sf in 2010? Even granting one whopper for the sake of the story(usually ftl)? I imagine that the answer would be no. But Bujold has the advantage of twenty to thirty years of development over Niven, so perhaps that's not really fair. After all, she has the benefit of his highly analyzed mistakes. And the same for any for any of a number of other artists formerly known as "hard".

Bujold writes hard sf, it's just she has characters more than a micro thick and thus people are distracted from that.

Does Julie Czerneda count? I've read very little of her work, but I know she lectures on the science in SF and its use in education.

OT but how is Czernada btw? I've seen her advertised in the back of Cherryh books published by Tor but heard exactly nada about her from fandom (at least, those parts I swim in) – is she worth checking out at some point, and if so why?

Is this hardness in the sense of scientific accuracy, or hardness in the sense of having the puzzle-story, engineer-triumphalist hard SF attitude?

Yes, that. Thank you for articulating it. There is plenty of *accurate* SF that is not thought of as "hard SF" because what folks really mean by 'hard' is "my world, let me show you how much science research I did to build it".

Nancy Kress — Stinger, Probability trilogy, Steal Across The Sky, among quite a few others.

Gwyneth Jones, especially Life.