"Do not go gentle into that good night" is a poem in the form of a villanelle, and the most famous work of Welsh poet Dylan Thomas (1914–1953). Though first published in the journal Botteghe Oscure in 1951, it was actually written in 1947 when he was in Florence with his family. It was published, along with other stories previously written, as part of his In Country Sleep, And Other Poems in 1952.
It has been suggested that it was written for Thomas' dying father, although he did not die until just before Christmas 1952. It has no title other than its first line, "Do not go gentle into that good night", a line which appears as a refrain throughout. Its other refrain is "Rage, rage against the dying of the light".
The poem currently remains under copyright, but was made publicly available here [1] at poets.org (with the copyright holder's permission).