How to become a ghost while still living

Once, I became a ghost. There is a way.
I became invisible to the outer world through my own doing, by withdrawing from it.

I lurked just beyond the threshold, not living and not dead. I could see the true ghosts so much clearer from that vantage point, and at the same time, I became virtually invisible to those still living.

There is always the potential to become a ghost.
We must remain of the world to take part in it.