Nightside comes from the Mind of Simon R. Green.
The idea behind Nightside:
A man named John Taylor who has a gift to find anything with this special gift that he calls his Private eyes, his Mindís eyes, his Third eye. Taylor ran away from Nightside because everyone wanted him killed, from his futuristic Enemies, the Harrowing, to Walker and the Rest of Authorities (The Authorities are the ones that make sure the Status Quo at the very least stays intact in the Nightside.) It has been said that he is the Devil in waiting, the King about to come to his power, a villain or a good guy. Depending on how itís looked at. Throughout the books he spends his time being a private investigator in the Nightside, to find things no one else can find. In the Stories you learn about the creation of Nightside, and who created it, and who Johnís Mother really is (since that is the huge question in the Stories, because she left when John was but a mere child and everyone who knows about his mother wont tell him, but it is know she is one of the most powerful people in Nightside)
Throughout the Stories you find out that all creatures can exist in the Nightside, creatures you can be, or say exist. Creatures like:
Futuristic Creatures (Of any kind)
Pretty much anything that has ever been talked about in other novels or, folk tales. Or that you can imagine.
There are also places where you can find anything. And it means ANYTHING from:
Magical Lamps with Real Genies
Imaginary creatures you can eat
Items from different time lines
Items from the Past
Gods can walk the streets of Nightside, but they mainly stay in the Street of Gods, and can do nothing to Harm you. Because in the Nightside, Everyone is free.
You also learn that for each time there is a another present that could be of another you. There would be a male side, or a female side, there would be a probable time line in which you where never born, or where born with a disease that slowly kills you. But what is learned that it is nothing more that a Probable time lineÖ not something that actually happened, but shows that anything COULD have happened. It makes it even more dangerous when people can play with that power. There are also probable futures that can be decided depending on how you play your cards.
Throughout Nightside that are Timeslips that can bring you back into the past, or a past that could have been probable, or into the probable future (remember, no future is set all future are merely probable with the same chance of happening, granted as things progress some futures can be wiped out and replaced by another one that has already been shown. If one future comes from so many different outcomes that one future is the more probable, but not decided!).
Anything you could wish of, thing of, resides in The Nightside. It was created so that neither Good nor Evil could play a part, where a personís fantasies could be played out in real life, no matter the horror of it.
Special gifts are like freckles in the Nightside, a human can enter the Nightside and have a special power, but once they leave Nightside that power is gone. The Nightside is a horrible, beautiful place, not meant for the faint of heart.
If you feel you are strong enough, then you are welcome. But remember, those of weak minds donít last long in the Nightside.