The only book by the writer/director of Orlando and The Tango Lesson about her daring, new movie starring Joan Allen, coming from Sony Pictures Classics in May. ''How can I describe Yes? Is it a love story? It's certainly romantic, but it is also quite definitely political. And it is also funny, though you couldn't really call it a comedy,'' says Sally Potter about the movie she began writing immediately following 9/11 as a response to the demonization of the Arab world in the West and the simultaneous wave of hatred against America. The story: She (Joan Allen) is an Irish-American scientist who is being strangled by her marriage to Anthony. She begins an affair with He (Simon Abkarian), a Lebanese surgeon exiled in London, who is working as a cook. Sam Neill plays Anthony, the betrayed and betraying politician husband, and Shirley Henderson is a philosophical cleaner who witnesses the trail of heartbreak the lovers leave behind them, as they embark on a personal journey through several countriesfrom London and Belfast to Beirut and Havanawhich forces them to evaluate their beliefs and each other. To have her characters better express ideas which might be abstract or hard to digest, Potter chose to write their dialogue in verse, though such is the narrative drive and the strength of the performances that for much of the time this seems like just a more lyrical version of everyday speech. She says of her choice: ''I read somewhere that in times of war the sales of poetry books go up. It's as though we need to use our most clear and rich tool, which is the tool of language, to express the subtleties and the nuances of our experience. And I think that verse is a kind of structure that allows us to explore language in a more interesting, more heightened way, than we tend to in everyday conversation.'' In addition to the complete screenplay and filmmaker's notes, the book includes essays written exclusively for this edition by the acclaimed, literary figures John Berger and Pankaj Mishra. 20 color photos.