Elizabeth Hitchener (1783–1821) is best known to literary history for a brief but intense friendship with Percy Bysshe Shelley, during which he declared her 'the sister of my soul'. When, in 1812, the friendship fell apart, Shelley turned on her. She was, he said, 'an ugly, hermaphroditical beast of a woman'. He labelled her 'The Brown Demon'. This Element is the first biographical and critical study of a schoolmistress, letter-writer, and poet, whose achievements transcend Shelley's denigrating characterisation. Drawing on fresh archival research, it uncovers a wealth of new information about Hitchener's life and shows how she benefitted from and engaged with late-eighteenth century traditions of radical and proto-feminist thought. It offers both a revisionary account of Hitchener's correspondence with Shelley-based on newly edited manuscripts-and her achievements as a poet, attending in particular to the generic and argumentative complexity of her topographical poem The Weald of Sussex (1822).