Do not go gentle into that good night
Don't succumb to the peaceful release of death.
Old age should burn and rave at close of day;
Rage, rage against [b]the dying of the light[/b].

Struggle against death, referred to here as [b]"the dying of the light."[/b]

The essence of this poem is struggling to survive; pressing on to live as long as you can in the face of death, even if it means suffering.

This was only a part of the whole. But I took it as reference and you gotta admit the name is cool. The even made a zombie video game with it.

And here's a link to an article explaining the meaning of the phrase. https://www.quora.com/Whats-the-meaning-of-the-poem-Do-Not-Go-Gentle-Into-That-Good-Night-1