Dylan Marlais Thomas (27 October 1914 – 9 November 1953) was a Welsh poet and writer who wrote exclusively in English. In addition to poetry, he wrote short stories and scripts for film and radio, which he often performed himself. His public readings, particularly in America, won him great acclaim; his sonorous voice with a subtle Welsh lilt became almost as famous as his works. His best-known works include the "play for voices" Under Milk Wood and the celebrated villanelle for his dying father, Do not go gentle into that good night. Appreciative critics have also noted the superb craftsmanship and compression of poems such as In my craft or sullen art and the rhapsodic lyricism of Fern Hill.

Dylan Thomas was born at 5 Cwmdonkin Drivein the Uplands area of Swansea, South Wales, on 27 October 1914 just a few months after the new house was bought by the Thomas family. Uplands was, and still is, one of the more affluent areas of the city, which kept him away from the more industrial areas. His father, David John ('DJ') Thomas, was an English master who taught English literature at the local grammar school. His mother, Florence Hannah Thomas (née Williams), was a seamstress born in Swansea. Dylan had a sister, Nancy, eight years older than he. Their father brought up both children to speak English only, even though both parents also knew Welsh and DJ was known to give Welsh lessons at home to children.

Dylan is pronounced in Welsh, and in the early part of his career some announcers introduced him using this pronunciation. However, Dylan himself favoured the anglicised pronunciation /ˈdɪlən/ his mother was afraid that the Welsh pronouciation would be corrupted into 'Dull One'. His middle name, Marlais, was given to him in honour of his great-uncle, Unitarian minister William Thomas, whose bardic name was Gwilym Marles.