Dylan Thomas wrote this villanelle for his dying father, using one of the most demanding fixed forms in English to contain overwhelming emotion. The rage against death is incantatory, the repeated lines functioning as both prayer and spell. Thomas was thirty-six when he wrote it, already drinking himself toward the death that would come four years later. The form gives the poem its power: the constraints force the emotion through a narrow channel, intensifying it beyond what free verse could achieve. Nineteen lines, indelible.