This is a pretty general question, but I will try to answer as well as possible using one of Thomas' most famous poems: "Do Not Go Gentle into That Good Night." First, one must realize that Thomas' poems as a group are almost always described as both "melodic," "romantic," and "having a definite voice." He was a grand fan of the villanelle, which is a type of nineteen-line poem with only two rhymes permitted and a very strict set of stanza requirements. "Do Not Go Gentle into That Good Night" is a villanelle. Considering that night represents death and light represents life, this poem challenges everyone (especially the "wise," "good," "wild," and "grave") to "Rage, rage against the dying of the light" and, perhaps, discover in the meantime just why life is so very precious.