->''"I don't want to achieve immortality through my work. I want to achieve it through not dying."''
Yes, we don't live forever. People and animals change as they age, and eventually catch disease and die.
Eternal life is ingrained in the collective human consciousness, having been present in literature and myths for [[OlderThanDirt as long as they've been around]]. Literally. ''Literature/TheEpicOfGilgamesh'' (the oldest heroic epic known to the modern world) is, in large part, about the titular character's search for a way to live forever.
Of course, having been around for so long, Our Immortality Is Different, and comes in several flavours. These tropes are not mutually exclusive; there's plenty of room for overlap.
* '''CompleteImmortality''' - A character simply ''can't'' die, ever.
** This trope = The Ageless + NighInvulnerability UpToEleven
* '''Retroactive Immortality''' - A character ''can'' die, but won't ''stay'' dead.
** BornAgainImmortality - if the character's mind or spirit is transferred to a new-born child, as in traditional reincarnation.
** ResurrectiveImmortality - if the character simply comes back to life uninjured, exactly as they were.
* '''Biological Immortality''' - A character is immune to the ravages of time, although usually still mortal to physical injury.
* '''Force of Will''' - A character so wants to live forever (usually to complete a given goal) that this sheer willpower is enough to scare off the Reaper.
* '''Spare Bodies''' - Any injury that would be fatal is OnlyAFleshWound for this character: his spirit will come back in another body.
* '''How to become immortal?''' - Methods by which a mortal character can actively cheat death. Key word being ''actively'', once the method is stopped or reversed, they either die or become mortal again.
* '''How to undo immortality?'''
* '''Incomplete Immortality'''
For general tropes relating to immortality, see ThisIndexWillLiveForever.