Eight short lines, four couplets, no punctuation and no capital letters: "Lunacy" looks as if it were written quickly, in the dark, by someone not quite awake. That fits a poem about the borderland between waking and sleep, between sanity and its loss, and between a present that is alive and a past that has decayed.
The poem opens with a bold claim: "the great sea / belongs to the present." The sea is always in motion, never finished, never the same twice, so it is easy to see why the speaker gives it to the present tense. Everything else, "all the rest already / is gone to rust." Rust is a precise image of time's damage. It is slow, orange-brown and flaking, and it eats iron, the hardest thing we build. The sea is liquid and restless, while the past is solid, brittle and corroded. The enjambment adds to the effect. The line "all the rest already" breaks off before it reaches "is gone," so the loss seems to arrive a beat ahead of the grammar, as if it had happened before we were told.
"Rest" is also the poem's quietest pun. In context it means "everything else," but it also means repose, and the last couplet undoes that meaning: the speaker is "raving in my sleep." The rest is rusted, and sleep gives no rest.
The third couplet is where the poem turns. "Where madness / is half moon" opens with a word that points to a place, but the place is not described like a real one. It is somewhere defined by a state of mind. The title helps here, since "lunacy" comes from the Latin word for the moon, and the old belief that the moon could unsettle the mind lives on in the word. The sea connects the two ideas. We know the moon pulls on the tides, so it quietly links the sea of the first lines to the madness of the last. Nothing is said outright. The reader has to make the connection, which is part of the poem's pleasure.
"Half moon" is a careful choice. A full moon would be the cliché of lunacy. A half moon is divided, and the phrase suggests a mind that is half lit and half dark, or half sane and half not. It also suggests the speaker is not fully gone, only halfway.
The final couplet is the most ambiguous. "shining so that it aches / raving in my sleep" has no punctuation to say who or what is doing what. The moon may be shining so brightly that it hurts. The speaker's mind may be shining and aching. The raving may belong to the speaker, to the madness, or even to the moon. Because the participles "shining" and "raving" float free, the subject and the world blur together, which is what happens in dreams. The phrase "shining so that it aches" is also a small piece of synesthesia, since light is given the feeling of pain. Brightness, usually a sign of clarity, becomes a symptom.
The poem has no rhyme and no regular meter. Its lines are short and uneven, running from about four to six syllables, and the absence of punctuation makes the line endings do the work of commas and full stops. Sound still holds it together. The long *e* of "sea," "already" and "sleep" echoes across the poem. "Madness" and "moon" share an initial *m*, and "rest," "rust" and "raving" share an *r*, a harsh, scraping sound that suits both corrosion and delirium.
What makes "Lunacy" worth reading is how much it holds in so little space. In its compression it resembles the haiku tradition, though it does not follow that form's pattern. It presents big ideas, time, loss and the fragility of the mind, through a few plain nouns: sea, rust, moon, sleep. It does not explain its own logic, and that gives it a dreamlike quality. The poem ends in the middle of the raving, so it is left to the reader to decide whether the sea, the moon or the sleeper is in control.