De la Mare's first novel, Henry Brocken, was published in 1904. Whether writing in prose or verse, for adults or for children, his vision revealed an unseen world that could be both beautiful and terrible, but was always mysterious. Come Hither (1923), his anthology of verse aimed mainly at children, is regarded as one of the most original ever compiled. In 1912, his collection of poems, The Listeners and Other Poems, contains in the title poem one of the most anthologised pieces in English literature.

Some of de la Mare's ghost stories, such as Seaton's Aunt, convey an atmosphere of barely-concealed terror and perversity behind a façade of respectability. Others have a fantastic but strangely beautiful quality which enables the reader to enter a world of deeper reality. His novel, The Return (1910), is a straightforward tale of terror where a dead man impresses his features on a living being. Memoirs of a Midget (1921), by contrast, achieves moments of great poetic fantasy without attempting to terrify the reader.