'If our love is a sin, then heaven must be full of such tender and selfless sinning as ours.' The Well of Loneliness is among the most famous banned books in history. A pioneering work of literature, Radclyffe Hall's novel charts the development of a 'female sexual invert', Stephen Gordon, who from childhood feels an innate sense of masculinity and desire for women. After relocating from Malvern to London and then to Paris, Stephen encounters fellow queer characters from all walks of life, from the sapphic salon hostess Valérie Seymour to the 'miserable army' of outcasts that frequents the 'merciless, drug-dealing, death-dealing' bars of Montmartre. Although Stephen and her acquaintances, allies, and antagonists are of their time, Hall's novel has offered support and solidarity to generations of LGBTQ+ readers, and it continues to shape debates about gender and sexuality today. This edition highlights previously overlooked points of influence, inspiration, and connections with other texts as well as situating the novel in historical contexts. In addition, the editors provide vital insights into Hall's engagement with religion, sexology, literary history, and popular culture.