DORY PREVIN, a singer/songwriter who generated a substantial cult following relatively late in life during the 1970s with her intensely personal songs, died on Tuesday at her home in Southfield, MA. She was 86. Her early success came in Hollywood, writing songs for the movies, generally as a lyricist working with her husband, André Previn, who later became a renowned classical composer and conductor. Their best-known collaboration was the theme from the 1967 film version of Valley of the Dolls, later recorded by Dionne Warwick. The Previns went through a very public breakup and divorce after he began an affair with Mia Farrow, then in her early 20s, whom he later married, and Dory had a nervous breakdown, spending several months in a psychiatric hospital. During her stay, she was encouraged to write down her feelings, and they emerged as poems, which she then turned into songs for 1970’s On My Way to Where (which contained her most famous song, “Beware of Young Girls,” about Farrow). It was the first of a series of confessional albums that polarized critics while bringing Previn a modest but devoted audience. She and her ex-husband reconciled as friends in the ’80s, and she came to loathe the fact that she was best known for their breakup. But as Bruce Webber points out in his obituary for the N.Y. Times, pain and grief were the foundation of her art. “I was always afraid to write music,” she said in 1970. “I wouldn’t have presumed to with a musician like André around the house. But I play a little guitar. So I started working them out on the guitar, thinking I could interest some singer in recording them, and that’s how all these songs were born.” Previn is survived by her husband, painter Joby Baker. (2/16a)