With each stanza of Dylan Thomas' "And Death Shall Have No Dominion," the theme (also the poem's title) is repeated for emphasis.
In stanza one, lines one and nine, the poem's title is given. The sentiment throughout the poem is that while the physical body may die, the spirit will not: in fact, the speaker believes the spirit of one who has died will become one with nature. There are several examples in this first segment.
"Dead naked men" will be inseparable from "the man in the wind and the west moon." After some carrion-eating creatures—birds or beetles, etc.—have removed all flesh from the bone, and even when the bone itself is gone, the spirit will be one with the stars, found at what was the "elbow and foot." (Sources note that this, among other lines—including the title—allude to Biblical scripture, but also insist that this is not a "Christian" poem, neither does it deal with God or the soul. With this said, however, it is also noted that these repeated references, such as "elbow and foot," refer to the Resurrection.)
Lines six, seven and eight all present paradoxes: seemingly impossible and self-contradictory statements. If we remember that the theme of the poem refers to the conquest of the spirit over death, the statements do make sense. One mad in life will be sane as his spirit joins with nature; a body that dies in the ocean may remain there, but the spirit will rise up (another allusion to the Resurrection); and, while lovers may be separated by death, their love will not be destroyed—this might go as far as to mean that when they are both dead, these spirits will be reunited...in nature.
The second stanza repeats the poem's theme. In this segment, however, the speaker relates several difficult—even horrific ways—one can die. "Under the windings of the sea" may refer to "currents," and the thought continues with "They lying long shall not die windily." Thomas' poetry is often hard to paraphrase: case in point here! Line twelve may mean that those who die under the water will not suffer a long time, exposed to the elements. Perhaps this is supposed to provide comfort for a "contained" and somewhat swift death under water as opposed to one passing away after agonizing hours (or days), left after as a rotting corpse, openly exposed. The next kind of death is one too horrible to imagine: dying on a rack or wheel, when the body is stretched beyond its natural capacity: sinews (tendons) may break, but not the spirit. One's "Faith" may even be broken into pieces. Now, for perhaps the poem's most difficult line:
And the unicorn evils run them through...
The unicorn is an imaginary animal. In some cultures, it has been associated with Christ, as well as with the Garden of Eden. Following "Faith...snap in two," I can only think that this line refers to the destruction of one's beliefs—perhaps one begins to feel faith as something imagined—perhaps there is even a sense of betrayal, as one's prayers seem to go unanswered in such ugly death...the spirit may feel as if it is splintering, but it shall not be...for death will be victorious.
The final stanza refers to nature. When one dies, the sounds of gulls and waves on the shore disappear. One dead cannot see a flower in the onslaught of rain. While a person may have been "mad" in life and now "dead as nails"—without sentience—and be "pushing up daisies" (a euphemism for death)...and even if the sun dies, death will not conquer the spirit.