Some ghosts are all lightning and fierce eyes, chains rattling and dramatic wailing. Some ghosts are made of mischief and mayhem, re-arranging furniture when backs are turned and laughing a silent laugh at shocked faces.
Some ghosts are made of centuries of tears, and just seeing them makes you feel sad for weeks after. Some ghosts seem like normal people, just a more see-through shade of real.
And some ghosts, ghosts like Grey Arthur, are made of cloud, with no firm edges, and aren't very ghost-like at all. Ghosts like Grey Arthur don't make you feel scared, or confused, or sad: ghosts like Grey Arthur you tend not to notice at all.
This didn't impress Grey Arthur one bit.
Grey Arthur wanted to be something more than nothing much at all, but in all honesty he simply wasn't very good at being a ghost. There are many different kinds of ghost, and Arthur had tried very hard to be most kinds with a few exceptions.
He couldn't bear to even try to be one of the Goons, because the sewers smelt something frightful on a summers day, and having to pull faces non-stop for weeks on end begins to make your jaw ache. But each time he tried he met with very little success.
Arthur's friend, Woeful William, was a Sadness Summoner. When William spoke it sounded like it was raining inside your head.
Centuries of being the most melancholy of ghosts had changed him from a dusty grey to the most depressing shade of blue, like the sky on a cold morning when everyone had forgotten your birthday.
When William sighed, all the normal humans who couldn't even see or hear William sighed too. William could do that to you.
Arthur had tried being a Sadness Summoner a few centuries ago, and had even written some thoroughly miserable poetry to go with it, but when Arthur smiled you smiled too, and this was strictly against Sadness Summoner Policy.
Arthur soon admitted defeat, but he didn't mind too much - being sad all the time was just far too gloomy.
Mrs Scruffles had once taken Arthur under her wing, and tried to help him become Faintly Real. Mrs Scruffles looked like an auntie you'd never met, with a chubby cheeked smile and her hair curled up in a neat little bun. She smelt of vanilla and freshly baked bread.
She didn't look like a ghost at all, which suited her just fine. You see, to understand the Faintly Reals, you must first understand the Ghost World.
The Ghost World sits right on top of the real world, like butter sits on toast; the unreal world thinly spread over the real, overlapping at the edges.
Ghosts walk down the same streets as humans, use the same buildings, even use the same lifts and sit on the same benches. The only difference is that humans, as a rule, can't see ghosts.
You could sit next to a ghost on a bus, and not even realise they were there.
Some ghosts liked the fact that the humans couldn't see them. Some ghosts didn't care either way, and some ghosts wanted more than anything for someone to notice them sat on a bench, or using a bus, or peering in through a shop window.
The Faintly Reals were ghosts that didn't really like being ghosts at all, and spent all their time trying to be as human as possible.
Some of the older Faintly Reals could even concentrate hard enough so that humans could see them, and they would go around pretending to be just like everybody else until they got too tired and faded back into invisible.
Sometimes, the only way to tell if a person was Faintly Real or actually real was to see whether or not they were slightly see-through when they stood in front of a light. That was always the biggest clue, and this was the reason why the Faintly Reals avoided discos.
Mrs Scruffles liked to be seen in terribly Real places, like the Citizens Advice Bureau, and in charity shops, and had once even spent a day as a substitute teacher. She was never so happy as when a human had mistaken her for Real, and engaged her in a very normal conversation.
"Could you give me directions to the bus station?"
"What a nice coat"
Mrs Scruffles would grin for hours afterwards, and tell anyone who would listen about her day spent in disguise as a human. The trouble was though, no matter how hard Grey Arthur tried, he couldn't look Faintly Real. In fact, he couldn't look anywhere near Real.
The best way to describe Grey Arthur, when he was concentrating as hard as possible to be as Real as possible, is that he looked as if he had been put together in a hurry.
When he remembered to have two ears, one was invariably a bit higher on his head than the other, and his hair looked as if it had been designed for someone with a different shaped head.
He looked like a boy, despite being nearly three hundred years old, but a boy who had been photographed with a shaky camera, and his edges were all blurred. When he wasn't concentrating at all, he was more cloud like than child shaped, and this annoyed him endlessly.
Mrs Scruffles had tried to teach him to look tidier, and she had tried to help him look as Real as possible, but even Mrs Scruffles knew when it was time to give in.
Arthur had nodded sadly, and accepted that he wasn't going to be Faintly Real. He'd never seen the attraction of spending time at the Citizens Advice Bureau anyway, if he was honest.
Arthur wasn't scary enough to be a Chain Rattler, or mean enough to be a Screamer. He wasn't naughty enough to be a poltergeist. Arthur wasn't enough of anything to do anything, and after he was busy feeling thoroughly miserable about it all one day, sat on a park bench where nobody could see him, when he heard something that caught his attention.
Now, it needs to be said that ghost's ears don't work like normal ears. Some ghosts don't even have ears, and those who do only have them for display.
Ghosts don't hear how loud or how quiet things are the way humans hear how loud or quiet things are: ghosts hear things in a completely different way altogether.
Ghosts hear by emotion.