This study examines rhythm, syntax, sound, and diction in selected early and late poems from Dylan Thomas's Collected Poems. It demonstrates, on the basis of stylistic evidence, that the later poetry is the greater achievement. The early and later poems are different in the area of rhythm. Early poems are regularly metered with a strong iambic beat, and a majority of lines are end-stopped. Rhythms in the later, finer poems are irregular, and enjambed lines predominate. The later poems show an increased ability to match rhythm with meaning. Dylan Thomas's syntax is simpler on the surface than ordinarily supposed. Early poems contain restrictive relative clauses that result in complex deep structure and sentence stacking. The later poems contain appositive relative clauses, a change in style that results in greater clarity. Repetitive patterning is frequent during both poetic periods. Thomas shows his greatest virtuosity in the area of sound. Many techniques are common to both periods, but his achievement in making sound functional in the later poetry gives it greater dimension. In creating his unique poetic voice, Dylan Thomas uses both old and new devices. Common and uncommon rhetorical figures abound in both periods, but, in common with the other stylistic …