Recently saw the Star Trek TOS episode “Who Mourns for Adonis?” and was wondering if there was ever a novel length SF treatment of the idea of Greek/Roman/Egyptian/? Gods as alien life forms. Anyone know of one?
Something along these lines can be found in Ilium and Olympos by Dan Simmons.
Roger Zelazney did the Asian Indian in Lord of Light, and the Egyptian in Creatures of Light and Darkness. I believe Keith Laumer did something based on Scandinavian gods.
Lester DelRey sent up the Aesir in Day of the Giants ( a heck of a good story despite its faults!).
There was also a truly bizarre story of which I can remember much of the characters and plot but not the author or title, involving the flooding of Atlantis (i.e., the Mediterranean Sea basin, up to that point dry land) thanks to the evil machinations of the Satrap of Egypt, Plu Toh Ra, whose daughter, Pan Doh Ra, is the love interest for Teraf and his brother Refo – yep, Epimetheus and Prometheus, and someone setting off an orichalcum bomb at the Gibraltar Dam. (This thing had more myths per square inch than a microfilm version of Bulfinch!)
Stargate?
H.P. Lovecraft.
Check out the anthology Other Worlds, Other Gods. There are several examples in that, including humans as gods to other people.
In that light, Theodore Sturgeon’s Microcosmic God is a classic.
Using technology as the basis of a religion, with “religious” powers being due to high tyech, shows up in Heinlein’s Sixth Column/The Day After Tomorrow and in Campbell’s All (which the Heinlein story is essentially a version of). I’asimov sorta does the same in his Foundation series. And I’ve kinda suspected these examples gave L. Ron Hubbard an idea for a science fiction religion.
Babylon 5 implied that the Vorlons had been meddling in the affairs of other civilizations for centuries, sometimes appearing in the guise of religous figures peculiar to a particular planet. For example, in the episode where Kosh saves Sherridan, most of the races present saw him as an angelic figure, with facial features consistent with those of the viewer’s species. Of course, Londo Molari saw nothing…but that’s another story.
It’s only the tip of the iceberg in the cosmos of the Samaria series by Sharon Shinn. It gets more convoluted than just “it was aliens”. And the gods aren’t so ancient. I liked the books a lot, but then again (as I always warn people in these threads) I also like Mercedes Lackey, so beware my taste in sf.
Chariots of the Gods?
He asked innocently.
A-heh, I don’t know if there are any novels for it, but…
The core concept of the entire Stargate franchise is built around the notion that all the gods and pantheons were just super-powerful/super-advanced aliens.
Arthur C. Clarke’s Childhood’s End is the obvious choice.
Just ducking in to point out that Star Trek V was on the movie channel today.
Actually, *Lord of Light * had humans in the far future, using advanced technology, taking on the identities of the Indian gods in order to rule a colonized planet.
In Mutineer’s Moon, many gods were actually members of one of two warring hi-tech factions stranded on Earth, which is why there are characters named Horus, Inanna, Geb, and Anu; they often used their real names, and are very long lived.
In Forge of the Titans the gods are actually extradimensional aliens, who took a human shape and personality in our universe because we were the first and only intelligent beings of matter they encountered, and they are too alien to operate in our world as they are. “Magic” by the way is a side effect of the exotic forces they bring with them, and died out when they left.
In Threshold, some of the “gods” were actually aliens trying to guide humanity, using dream communications and subconscious manipulations which were misinterpeted as communications from gods. This is done via exotic crystals which happen to be found for geological reasons under mountains, which is why Mount Olympus got a reputation for the home of the Greek gods, for example.
In Giant’s Star, the gods and magicians of old were enemies of Earth, who faked miracles and magic to divert us into useless paths of mysticism and religion, in order to slow our progress.
In Cyber Way, the gods ( spirits ? Whatever ) of the Navaho are extradimensional aliens, and the ancient myths heavily distorted and simplified versions of their doings. Earth and our entire universe are their constructs; basically, we are all just programs in their version of the Matrix.
As in Who Mourns for Adonis? aliens took on the identies, or posed as, Greek gods in order to rule ancient Greece. 
Legion of Super-Heroes Annual # 2 has Durlans presenting themselves to ancient Romans as gods.
The Atlantis Chronicles implies that the gods of the ancient Egyptians were actually Atlanteans (not quite aliens, but similar in ways).
The short story “I Am Returning” by Ray Russell explains how everything about western religion was due to aliens. In 1700 words.
I remember reading a book years ago - I think it was by Fred Saberhagen - that involved an alien machine/computer/entity called A-Ten ithat ended up in ancient Egypt. Or something like that. It was very forgetable, obviously. I can’t recall anything else about it.
Not quite science fiction, but Douglas Adams’ *The Long Dark Tea-time of the Soul *features a number of Norse gods misbehaving in and around London.