''Affinity'' is a novel by British author Sarah Waters, first published in 1999. It explores a dark period in the lonely life of Margaret Prior, a youngish spinster from a wealthy English family. Margaret begins visiting a women's prison as a means of escaping her own ennui and in the hopes of being a positive role model for the inmates. There she meets a young prisoner, Selina, with whom she becomes infatuated. But it is unclear what the mysterious inmate's motives are...

A [[http://www.imdb.com/title/tt1116182/ film adaptation]] followed in 2008.


* AdaptationDistillation: The TV adaptation replaced [[spoiler: Margaret realising she is a lesbian after falling in love with her future sister-in-law Helen]] with [[spoiler: Margaret becoming attracted to women after her fiancÚ tries to rape her]].
* {{Angst}}
* ButchLesbian: [[spoiler: Ruth Vigers, who successfully passes herself off as Selina's male spirit guide in order to seduce and/or sexually abuse young girls at seances. This also qualifies her as a variant on the PsychoLesbian trope - Waters (obviously) isn't arguing that lesbianism is evil, but this particular lesbian definitely comes across that way.]]
* DarkAndTroubledPast: most of the characters in the story.
* DrivenToSuicide: A year before the novel begins, Margaret attempts a fatal overdose of sleeping medicine after learning that her female lover is planning on marrying her (Margaret's) brother. [[spoiler: Margaret's narrative ends with her about to attempt suicide again after she learns that Selina has betrayed and deceived her. This second attempt is implied to be successful.]]
* EeriePaleSkinnedBrunette: Margaret is one.
* {{Gayngst}}: The primary source of Margaret's depression, following her ex-lover's marriage to Margaret's own brother.
* PsychicPowers: Selina works as a psychic medium, and claims to commune with [[OurGhostsAreDifferent spirits]].
* QueerRomance: Between Margaret and Selina and Margaret and Helen. [[spoiler: Also Selina and Ruth, and (depending on your interpretation) Selina and Mrs Jelf]].
* SpookySeance: Selina works as a spirit medium before being sent to Millbank.
* VictorianBritain: set in this era, and very much characteristic of its darker elements.
* VictorianLondon