"Out of the Dust" by Karen Hesse is a novel written in the form of free verse poetry. Free verse poetry, as the name indicates, is free from the limitations imposed by rhyme and meter. It is not very common for novels to be written with free verse poetry, but the lack of limitations creates a more authentic experience as the story is put forth by the protagonist, Billie Jo Kelby. The absence of rhyme and rhythm more closely follow the patterns of normal speech.
Free verse was popularized by the Imagists, poets who prioritized the content of their writing over observing the "norms" of poetic writing. The Imagism movement occurred in the early 20th century and served as precursor to the modernist movement. Walt Whitman and Emily Dickinson are considered by many to be the most prominent English-language free verse poets.
There are many great examples of free verse poems available on yourdictionary.com. One of my favorites by Walt Whitman is "After the Sea-Ship," a great example of the free-flowing style found in free verse poetry.