Dylan Thomas’ “Prologue” is Thomas at his best. A recording of the poet reciting the poem can be found here:

He has a magic way of writing that very few even try to approximate. Consider these first lines:

This day winding down now
At God speeded summer’s end
In the torrent salmon sun,
In my seashaken house
On a breakneck of rocks
Tangled with chirrup and fruit,
Froth, flute, fin, and quill
At a wood’s dancing hoof,
By scummed, starfish sands
With their fishwife cross
Gulls, pipers, cockles, and snails,

Consider how he creates these effects.

First, he simply avoids adjectives. He describes things, but he avoids limp adjectives. Many (poor) writers attempt to make their writing powerful by piling up emphatic adjectives — but that is like putting a repainting job an old car to make it drive faster. Use adjectives only when nothing else will do — and then only use the necessary adjectives.

(The same applies to unnecessary adverbs. Writing the word “clearly” at the beginning of a sentence makes nothing which follows “clear”. If the sentence is not clear, the adverb will not make the thought penetrable. If the sentence is clear, calling it “clear” is silly.)

Rather than rely primarily upon adjectives or adverbs, Thomas uses verbs. It is not merely “summer’s end” but it is “God speeded”. The summer is not coming to end an, God is forcing it forward.   The house is “sea shaken”, the rocks “breakneck” — you can feel the slippery slime and cold water beneath your feet as you work your way among the rocks.

Second, he cares for the sounds, “froth, flute, fin …” “scummed starfish sands”. The density of the alliteration & assonance require one to read slowly — provided one reads out loud (which one always should with Thomas).

Third, he draws images together in uncommon and arresting ways, “torrent salmon” — that makes some sense – but he adds a final, “sun”, “torrent salmon sun”. What is a “salmon sun”? Is it the color of the sun, the fish coming up the river in a torrent?

Consider these words

Geese nearly in heaven, boys
Stabbing, and herons, and shells
That speak seven seas,

The geese are set to leave this world — but the human boys are stabbing — just like the herons; and the shells speak.

Fourth, the rhythm is insistent, coupled with short lines (six syllables) forces the sight forward. Yet this contrasts with the fact that nothing happens: he is merely looking out the window for his “sea shaken house” upon the “sunset nets” and “geese nearly in heaven”.

The first action which takes place is his singing

At poor peace I sing
To you strangers

Indeed, the poem is merely the poet singing on the shore. In drawing out this image, Thomas harkens back to the priest of Apollos wandering by the sea

The old man was terrified. He obeyed the order/turning, trailing away silence down the shore/where the roaring battle lines of breakers crash and drag. And moving off to a safe distance, over and over/the old priest prayed to the son of sleek-haired Leto,/lord Apollo, “Hear me Apollo …” (Fagels, which is the best English translation by far; you have not read the Iliad until you have read Fagels.)