Bettina von Arnim, née Elisabeth Brentano (1785-1859), German writer. Sister of the Romantic Clemens Brentano and wife of his associate Achim von Arnim, she published her correspondence with her friends, such as the German writer Johann Wolfgang von Goethe. In Goethe's Briefwechsel mit einem Kinde (1835; Goethe's Correspondence with a Child, 1837) she added imaginative touches to the letters, making them almost fiction. Later she dropped Romanticism for liberal and political treatises, as in Dies Buch gehört dem König (This Book is for the King, 1843), a tract for social reform.