Authoress and reformer. Born in Edinburgh, into a noted family, which included evangelists Robert (1764 - 1842) and James Haldane (1768 - 1851), Haldane was the sister of physiologist John Scott Haldane (1860 - 1936) and politician Richard Burdon Haldane, Viscount Haldane of Cloan (1856 - 1928). She studied nursing and worked in the Royal Infirmary of Edinburgh. She served on various regulatory and advisory boards relating to the nursing profession, founded an organisation for slum redevelopment in Edinburgh (1884) and was involved in the management of social housing.
Haldane wrote biographies and translated several philosophical works. She wrote a Life of Descartes (1905) and edited his philosophical works, translated the German philosopher Georg Wilhelm Friedrich Hegel, and wrote commentaries on George Eliot (1927) and Mrs Gaskell (1930).
In 1920, Haldane was appointed the first female Justice of the Peace in Scotland.
She retired to Auchterarder, where she died.