Psionics and Extra Sensory Perception are the abilities to use the power of the mind for many types of use for which most people think would be impossible, for example levitation, moving objects and reading another persons mind. A psion is someone who has mastered these arts and can use their abilities to their advantage. The most common types of powers that psions possess are usually some sort of telepathy - the power to read or manipulate thoughts - and telekinesis - the ability to move items using the power of the mind alone. However, there are many other sorts of ability, including the power to see events that are happening far away and even to cause damage to another person via a "mental attack". It is even possible that even the "sixth sense" that some people allude to having is a minor psionic power.
In any event, people with psionic power are very rare, probably only one person in every 100,000 has some sort of psychic ability, and then most of those have only low level powers, such as telepathy and telekinesis. Which would mean at most, that there are around 30,000 psions of varying abilities roaming the world.
Since before the Second World War various secret departments in many military and non-military organisations have tried to use psionic powers to their advantage and have tried to train individuals in their use, but it was not until 1984 when President Heston officially set up the ESP Division in the US Government. While made public, the ESP Division is actually a quiet organisation with the goal to look into psionic powers, their uses, who has them, can people be trained to learn psychic powers and the like. Over the following years the ESP Division would have mixed fortunes. They - like other organisations after and before them - would learn a little bit about the powers and their uses and they would be able to help people with powers along in their development, but they would not be able to create people with psychic power. Instead, the psions trained by ESP Division would be loaned out to other governmental departments as advisors, using their limited powers to aid investigations, with many mixed results.
The issue seems to be that people are born with psychic ability and these people can be trained to use their powers and even expand on them. But people who aren't born with the ability can't be trained to use them. Why people have the ability and others don't is one of the great mysteries - is mankind changing? are these people mutations? is it simply latent and people just need a 'nudge' in the right direction to get it to work?
However, it isn't only the US Government that is experimenting with psions, many corporations too have secret departments studying ESP and the people who can use the abilities. Like the US government, they have also come up against brick walls, but unlike the government, they have much more in the way of resources that they can throw at their projects and if anyone can crack the mystery, it is they.
Because of the inability to train non-psions, Corporations and governments are always on the look-out for people with special powers, and when found these people are "persuaded" to join the organisation and put their powers to use for the 'good of humanity' or just for lots of money. Obviously some corporations use more heavy-handed techniques than others, and naturally some of the psions don't wish to work for anyone else.
Psionic powers are abilities of the mind and follow most traditional teachings; powers can include telepathy, telekinesis, mind control, levitation and the like. However while there are other powers, violent powers are rare and the ability to kill someone using thought alone is something that eludes most people - the most that the majority of psions can do is to cause a headache. But obviously there are exceptions and these people with greater abilities are in high demand.
The general public is probably very sceptical about psionic powers. Psions and organisations don't tend to advertise their programmes, let along when a psion is actually in their area. To most people, psionics and ESP are simply science fiction that you watch on television. Conspiracy theorists know otherwise of course, after all, the government has been scanning your mind for years now and the announcement of the ESP Division was simply a clever ruse to divert attention from their real plans of controlling the population.
The average person though, will never met a psion (but how would they tell?) let alone experience any psionic activity, although with all the strange activity happening in the world, maybe people are aware and just keep quiet.
After all, if you start showing strange abilities who knows who'll show up on your door?
Psions should only be used with the gamesmasters permission as they can unbalance games quite dramatically, as they can have the power to delve into someone's brain and find out just what is going on. However,
Psions are probably best left as NPCs, with the characters hired to track down a psion or to protect one from rival corporations or gangs. Of course, it could be a player character that has the powers and needs the protection.
Psions are currently born with their power rather than given it, but this power may not choose to manifest itself straight away. It is possible that some people may go through their entire lives not realising that they have hidden talents. Some people seem instinctively to know they have the power when they hit puberty, while in some cases it takes some incident for the person to start using their abilities.
However it comes, once the psion knows they have psionic ability then they can be trained and awoken to the fact that they might have other talents then just their basic ones. Their lives may then get better as they are offered jobs offers from shady corporations, or spend the rest of their lives as lab rats for other corporations.
The most common use of psions is in the area of surveillance. Most psions have some kind of telepathic ability and this is used in many ways, from reading surface thoughts to planting false memories. The psion is thus the ultimate modern day spy.
See here for full psionic rules in Highwayman.