This film, part of the BFI Gothic season, also screens on November 21st and 24th. Details here.
Chicago Reader review:
'The treacherous-mate theme that has been a staple of “women's pictures” since Gaslight gets its ultimate, most agonizing development in this 1968 story about a young woman (Mia Farrow) who discovers her husband has sold her body for use by a witches' coven. The horror is more clinical than supernatural, as Polanski transforms Ira Levin's story into a metaphor for the loss of identity induced by pregnancy. A very sophisticated, very effective piece of work spun from primal images, with an excellent cast that includes John Cassavetes, Ruth Gordon, Sidney Blackmer, Ralph Bellamy, Maurice Evans, Patsy Kelly, and Elisha Cook Jr.
Here (and above) is the trailer.