h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

from the D&D Glossary> "Astral Plane: An open, weightless plane that connects with all other planes of existence and is used for transportation among them. Certain spells (such as astral projection) allow access to this plane."

What exactly this means is dubious, of course, but it gets the general idea across, perhaps. From memory, astral projection involved a long stretchy blue 'string' which reached between your astral projection and your body in the material world. Anything breaking this string would cause madness and all kinds of trouble. And there are various scary monsters which roamed the astral planes - and other denizens with their own agendas - and you had to watch out for vortexes in the astral plane, too - which could rip your projected body to shreds!

It was all good fun - I wonder how much of what was in that is reflective of 'real' astral projection - and how much was added for gaming purposes...

Another gaming system, Shadowrun, has another interesting take on astral projection. You must have magical ability to see the astral plane, which means you can look at people's auras and detect magic in the area. Astral projection is the act of leaving your body behind and letting your soul exist entirely in the astral plane. Only another magical person can see your astral self after it has left the body.

Your soul travels very quickly, and can travel to places your body can't go. For instance, your astral self can walk through walls. The bad side is that your body is left behind like a mindless lump, so it can be killed easily by the enemy. The usual solution is to warn a party member before you go astral and have them guard your body while you are away.

If your body is killed while you are astrally projecting, your astral self fades away within a matter of minutes. If your soul is killed by another magic user while you are astrally projecting, your body continues living in a permanent coma.