Alien races in science fiction who don't want any other race to know of their existence

He was just one dude, though.

The aliens in William F. Nolan’s “The Last Three Months.”

A reporter starts wondering why everyone has had car problems lately. Turns out it’s a fiendish plan by aliens, who run all the repair shops – if you car is broken, you get frustrated and don’t pay attention to the fact they’re taking over.

The two alien species in Frank Herbert’s “The Featherbedders” don’t want any humans to realize that they are there. The same applies to the aliens in Tenn’s “Lisbon Cubed”.

If a species living openly but hiding their intelligence counts like with Futurerama’s Nibbler, there’s the short story Into Your Tent I’ll Creep, where the species hiding its true intelligence is

…dogs. The protagonist and a friend have a conversation where the friend explains his theory about how dogs are just as smart as humans but are hiding it, basically living off of us. The protagonist scoffs a bit, then as they are leaving a dog rushes past, and trips the friend down some stairs where he breaks his neck. The dog stops…looks the protagonist right in the eyes…then runs away.

I recall a sci-fi short story where a scientist discovers evidence of a new class of animal life, one that had evolved perfect transparency; in other words it’s naturally invisible. He has two other immediate realizations; first, that there’s no way that science should have missed something like that for so long. And second…he looked up and announced to the empty air that “you know, if you kill me it won’t stop people from finding out about you sooner or later.”

What about the Second Foundationers in the original Foundation trilogy? Not sure if they count as a separate race, but they have unique mental powers.

The g’Kek in David Brin’s Sooner trilogy (Brightness Reef, Infinity’s Shore, and Heaven’s Reach). The race had been in a quasi-war which was going against them. One group, anticipating an unfavorable outcome, went into hiding on a backwards planet. Which turned out to be a good idea because the war went against the g’Kek and as a result, the race was exterminated. So the refugee g’Kek had to remain in hiding because if they were discovered, they would also be exterminated.

There’s pretty good evidence they are that paranoid,

If you’ve only met extremely atypical members of a species and have never visited their homeworld or even know where it is, is that species really known to you?

Oooh, my Tree-of-Life roo . . . errr, yams are done, must eat now!

CMC fnord!

Ahem. Puppeteers.

Also Hal Clement’s novel Eye of the Needle, and sequel Through the Eye of the Needle, which used the same concept. Also Larry Niven’s short story “The Meddler”.

When I was a kid (early to mid 1970’s), I saw a TV show in which two groups of aliens were running around Earth trying to kill each other. They were disguised as humans, but with a special pair of sunglasses, you could see their true forms. (and this was at least a decade before They Live.) Whichever group won, would get to control Earth. Both groups were eventually killed by a woman who turned out to be a member of a third alien culture, that wanted Earth to stay neutral in this cosmic Cold War. I wish I could remember the title.

Clement’s first novel was Needle, and the sequel was Through the Eye of the Needle. Sorry about that.

They don’t seem to cae about humans…but what about other races?

Near the end of Poul Anderson’s Brain Wave, the space-faring human beings don’t want the non-space travelling aliens to know about them. Kind of a turnabout on the usual situation, butit makes sense in the logic of the story.

Well, they didn’t stay secret, but they were secretly observing humans, kzinti, and others while remaining hidden before most of the Known Space stories take place. They even kidnapped a ship full of humans and brought them home to study for a few generations. So, for part of their history, they’d definitely qualify.

If anyone isn’t familiar with the Puppeteers from Niven’s Known Space - they did this because they’re a race of extreme cowards.

I’m thinking Zenna Henderson’s The People *might *qualify - they seem to be human (and can actually reproduce with humans) but are not from Earth and have some rather distinct abilities. They’re sort of hiding in plain sight, but they don’t want the Earth humans to known about them as they’re refugees smart enough to know what happens to feared minorities.

On NEUTRON STAR by Niven it is mentioned specifically that they are cowards, and resort to blackmail, I loved the part when the test pilot survived the gravitational tides when attempting to do the same maneuvers that killed the passengers in another ship that the puppeteers made, if it is shown that it was not a failure of design then the puppeteers could continue to export and sell them.

[Spoiler]Puppeteer: “If you will talk to reporters now, explaining what happened to the Institute ship, we will pay you ten thousand stars. We will pay cash so that you may use it immediately. It is urgent. There have been rumors.”

Shaeffer: “Bring 'em in.” As an afterthought I added, “I can also tell them that your world is moonless. That should be good for a footnote somewhere.”

“I do not understand.” But two long necks had drawn back, and the puppeteer was watching me like a pair of pythons.

“You’d know what a tide was if you had a moon. You couldn’t avoid it.”

“Would you be interested in-”

“A million stars? I’d be fascinated. I’ll even sign a contract if it states what we’re hiding. How do you like being blackmailed for a change?”[/spoiler]

It’s a comic-book, but I think JLA: HEAVEN’S LADDER is worth mentioning.

“They countered solitude with curiosity,” says Aquaman, upon telepathically making first contact, “roaming and cataloguing our cosmos with an emotionless. scientific detachment.” But we soon learn that “these beings are the ultimate isolationists. They’ve never ‘sullied’ themselves with any sort of outreach.” Instead (putting aside, for the moment, how a sizable number of zealots among them “are adamant against intermingling their sentience with ‘lesser’ lifeforms like ours”), the slightly-more-broad-minded members of that species were able to look past “how much like bacteria we are to them” by seeding other planets “with ‘sleeper agents’ disguised to infiltrate each culture and master its predominant concept of the hereafter.”

Yes, you read that right: technologically, they’re so far ahead of us (and, this being a DC comic, of the futuristic worlds that show up in Adam Strange’s comic, and Hawkman’s comic, and so on) that the only field they figure could justify arm’s-length covert research among “paramecia” is the mystery of religious faith, which fascinates them as a uniquely alien concept of limitless value.

Except, as the Atom argues (after apparently winning his bet with the Flash, upon learning that the Pope ain’t our world’s secret sleeper agent), “that isolationism – that’s blinded you to any sense of spirituality! The distance you create between you and us is the same distance that separates you from a greater divinity! When you stand apart – you stand alone! Please! Since the beginning of time, you’ve known nothing but solitude…”

…er, it goes on like that for quite a while, but you get the point: they want to construct an extradimensional “heaven”, they’ve thus explored the universe to pattern a synthetic deity on whatever second-hand insights they can acquire without bothering to interact with other life-forms – and, of course, “because you’ve sailed in the solitude of egotism, you’ve gotten nowhere!”

There’s also Larry Niven’s humourous story “The Nonesuch” that features an alien predator that uses its telepathic powers to be incredibly good at hiding. Of course, there are disadvantages to having people think you don’t exist…

There was an alien race in an issue of She-Hulk that sued the Watchers because they wanted to keep their existence hidden from the rest of the universe, and felt that by being observed by the Watchers that would be impossible. She-Hulk served as judge in that case.

I remember there was talk that they were the Furlings…
What about MIBs? One flash of light and you think all you saw was light from Venus being refracted by swamp gas.

Not aliens, though. At least, not in the movies. Never read the comics.