Poetry that does not rhyme is called free verse poetry. Free verse poetry does not have a rhyme, but the poems still have a meter or a beat to them that overlays the work. This fact has led many people to say that free verse is not totally free because it still has a pattern and a rhythm, despite lacking rhyme.
There have been many opponents of free verse poetry, including such famed authors as Robert Frost, who likened the style to playing tennis without a net. There have been just as many in favor of the style, such as Carl Sandburg, who said that poets who lacked the imagination to play Frost's proverbial tennis without a net lacked imagination.