Grant had just finished his first novel, Men of Mercury, set on the eternally sunward face of the innermost planet, when radar Doppler studies first showed that the notion of a tide-locked Mercury was a myth. So he got to work on Venice, Venus, and finished it just in time to see the space probe data indicating a severe lack of water on the erstwhile Planet of Love, not to mention surface temperatures of 700 Kelvin. Somehow, he couldn't see gondolas on canals of molten lead. Bye-bye novel number two.
Such disappointments would have discouraged some men, but Grant Miller was not some men. He was the seventh son of the seventh son of a family of occult gypsy crackpot inventors. His heritage granted him access to certain...secrets.
Making use of various arcane family devices (in the broadest sense of the word) Grant summoned an entity with peculiar powers and abilities and whose nature was to use those powers on the behalf of one who summoned it. If Grant had been a fantasy writer, the entity would have been a demon. Since Miller was a science fiction writer, we may be assured that the entity was an alien being of some sort, or from another universe or something. But not a demon. Definitely not. However, its name was Damon. It could only be summoned after sunset; no one knew why.
"So!" said Damon, who was difficult to see, thus saving much in the way of gratuitous description. "I am here and cannot return until I have performed the tasks you set for me. What are your desires?"
Grant pointed to his manuscripts. "I wrote those in good faith," he told Damon. "It's not fair for Science to keep yanking the rug out from under me."
"So I want it back the way it was, so I can sell my stories. While you're at it, you might put some canals on Mars, so I can start my next book, Mars Merchants."
"Ah," said Damon. "Manipulation of matter. Easy. Shouldn't take long." He vanished with no trace whatsoever of smoke or brimstone. Really.
Within a few weeks it was discovered that an odd solar effect had been giving false radar images of Mercury. These subsided and embarrassed scientists announced that Mercury was tide-locked after all. Faces became even redder when it was learned that the most recent Venus probe, despite precautions, had somehow been contaminated with an algae that was slowly converting the upper layers of the Cytherian atmosphere into oxygen and water vapor. The algae rain would continue until the entire atmosphere was transformed and the planet became a swamp.
No one wanted to talk about the sudden appearance of strange markings (canali) on the surface of Mars. No one who did talk had any credible explanations.
So Grant Miller set to work on his third book, while sending his first two out to agents and publishers.
Several months later, he again summoned Damon.
"Look," he said to the alien. He pointed to his desk. "Rejections. Letters, slips, notes. Piles of them. This is no good. The publishing industry is too close-minded. They don't recognize a fresh approach. I want you to sell my books. Be my agent. Make them buy them."
Then he said, "I've stopped a planet in its tracks. No problem, a simple application of the Joshua effect. Water on Venus? A little bio-engineering and some transmutation. Cookbook stuff. Canals on mars? Simple. You want life on Jupiter, Saturn, even Pluto? Can do. Sea monsters? Plagues? A rain of fire? All in the operating manuals. My powers are vast and utterly at your disposal. But..." He sighed again.
"But you ask me to sell your fiction for you. I would have to get editors to read them. All the way through. I would have to make them like what they read. I would have to make them think that other people would read them and like them. I would have to get publishers to pay money for them!"
"I'm sorry," Damon said. "I'm powerful, very powerful. But there are some things even I can't do."