In 1921, American poet H.D. collected and published a selection of previously published poems by Marianne Moore. Although this angered Moore, as it was entirely unauthorized, she later accepted the edition as well made and used it as the basis for her own 1924 publication of Observations. Moore's unique poetry matches the experimentation underway during the American Modernist movement. Much of it incorporates seemingly out-of-place quotations into complex free verse that often uses Nature as a subject matter.