“Do Not Go Gentle into That Good Night” is one of the best-known villanelles composed in English. The villanelle form, which is originally French, consists of five tercets followed by a final quatrain. What makes the form unique is its use of two interweaving refrains, which are introduced as the first and third lines of the opening stanza (bolded here):

Do not go gentle into that good night,

Old age should burn and rave at close of day;

Rage, rage against the dying of the light.

These two refrains alternatingly recur as the concluding lines of the middle four stanzas. Finally, they appear in tandem as the last two lines of the final stanza. Villanelles use only two end rhymes: the two refrains, as well as the opening line of each stanza, follow the A rhyme (“night,” “light,” “right,” etc.), while the second line of each stanza conforms to the B rhyme (“day,” “they,” “bay,” etc.). This constrained range of rhyme makes for a dense sonic palette and contributes to the poem’s intense emotional pitch. More generally, this repetition—of phrases and of sounds—suits the speaker’s straightforward and passionate tone, his call for defiance and resilience in the face of death. The speaker’s exhortations are rendered more urgent and earnest with each successive recurrence. In this way, Thomas convincingly leverages the villanelle form for his own thematic and tonal purposes.

Just as Thomas uses a limited range of end rhymes, he uses a limited set of images and metaphors, drawing only from the natural world. The poem’s central metaphor, repeated and elaborated throughout, compares life to day and death to night. The poem’s opening tercet, which contains the two refrains, establishes this conceit, referring to death as “that good night” and to old age as “close of day,” a time marked by “the dying of the light.” Thomas adds to this metaphor in the fourth stanza:

Wild men who caught and sang the sun in flight,

And learn, too late, they grieved it on its way,

Do not go gentle into that good night.

These lines extend the conceit by specifically comparing the passage of the sun across the sky to the course of a human life. In this context, Thomas uses the metaphor to depict those who have taken such delight in life that they have been woefully ignorant of its brevity. This metaphor is one of the most fundamental and ancient poetic tropes, but Thomas avoids cliché by presenting it in a declarative, passionate, and surprisingly ferocious tone. The sunset of life is often the occasion for melancholy meditation, but in Thomas’s hands, it is the occasion for an urgent, raging grief.

Thomas’s other natural metaphors range from the marine to the meteorological. The third stanza presents an elaborate metaphor that describes the works of ethically driven people as “frail deeds [that] might have danced on a green bay” as the “last wave” passes by. Here, the bay is life, or perhaps reality more broadly, while the waves mark the passage of human existence, each one representing some unit of time. The “dance” of the deeds upon the water is a somewhat abstract image, but it seems to evoke the play of light or of reflections on turbulent water, underscoring the transience of those “good” actions. The second stanza conveys the futility of the “wise men” and their learning by indicating that “their words had forked no lightning.” This oblique metaphor compares the desired achievements of the wise men to the splitting of lightning. This image says as much about the loftiness of their aims as it does about their failures. The “grave men” in the fifth stanza come to a realization that their eyes, rendered “blind,” could “blaze like meteors and be gay.” This metaphor is surprising, because meteors, often associated with destruction, are used here to convey joy, vivacity, and perhaps a form of prophetic vision. Altogether, Thomas’s metaphors and images, archetypal and elemental as they are, contribute a timeless character to the poem.

One of the primary devices Thomas uses in the poem is opposition. Each point along the poem’s progression features some form of opposition, whether thematic or syntactical. Indeed, the poem’s fundamental stance is to “rage against the dying of the light,” an attitude defined by negation and resistance. The second stanza creates syntactical contrast with its use of “Though” and “Because,” framing the deaths of the wise men as a clash between knowledge and longing. There is opposition, too, in how the wild men retrospectively understand that their singing was always a form of grieving. The final two stanzas present opposition through the paradoxical phrases “blinding sight” and “fierce tears.” The latter phrase in particular encapsulates the oppositional dynamic of the entire poem, with its potent tonal mixture of anger and sorrow. The poem’s central conceit, too, is an opposition of day and night, life and death. What the poem implies is that this opposition is in fact a cycle, and so time’s ceaseless passage will bring the speaker’s own day to night, occasioning the same “fierce tears” his father now sheds.