British author and biographer best known for his brilliant and unconventional biography The Quest for Corvo (1934).

Family economic difficulties obliged Symons to leave home and learn a trade at an early age. For three years he lived a life of drudgery, working as an apprentice to a furrier. His formal education was private and scanty; Symons considered himself self-educated and, as a writer, self-made. Employed as secretary and later director of the First Edition Club of London, he became a skilled bibliographer, an occupation he considered dreary and uncongenial to his personal literary and cultural aspirations.

His well-received biography H.M. Stanley (1933) was followed by his magnum opus, The Quest for Corvo, a biography of the English author and eccentric Frederick Rolfe (Rolfe, Frederick William) (1860–1913), the self-styled Baron Corvo. Rolfe's life had fascinated Symons for years—an earlier work, Frederick Baron Corvo, had been printed privately in 1927—and his approach to the subject in The Quest for Corvo, subtitled “An Experiment in Biography,” was novel in its anecdotal, fragmentary reconstruction of a life about which little factual evidence existed. The book won critical acclaim and came to be regarded as a masterpiece of modern biography.

Symons' other works include Emin, Governor of Equatoria (1928); A Bibliography of the First Editions of Books by William Butler Yeats (1924); the Anthology of 'Nineties Verse (1928), compiled and edited by Symons; and an uncompleted biography of Oscar Wilde.