Tibetan Book of the Dead

commentary by Chogyan Trungpa:

"Imagine a person who suddenly wakes up in hospital after a road
accident to find she is suffering from total amnesia. Outwardly,
everything is intact: she has the same face and form, her senses and her
mind are there, but she doesn't have any idea or any track of a memory
of who she really is.

In exactly the same way, we cannot remember our true identity, our
original nature. Frantically, and in real dread, we cast around and
improvise another identity, one we clutch onto with all the desperation
of someone falling continuously into an abyss. This false and ignorantly
assumed identity is "ego."

So ego, then, is the absence of true knowledge of who we really are,
together with its result: a doomed clutching on, at all costs, to a
cobbled together and makeshift image of ourselves, an inevitably
chameleon charlatan self that keeps changing, and has to, to keep alive
the fiction of its existence.

In Tibetan, ego is called dak dzin, which means "grasping to a self."
Ego is then defined as incessant movements of grasping at a delusory
notion of "I" and "mine," self and other, and all the
1. concepts,
2, ideas,
3. desires,
4. activities
that will sustain that false construction.'