Film critic STEPHEN SCHIFF reviews "From Dusk Till Dawn" the new film starring George Clooney,... Film critic STEPHEN SCHIFF reviews "From Dusk Till Dawn" the new film starring George Clooney, Harvey Keitel, and Quentin Tarantino.INT. 2 : Sexologist LEONORE TIEFER. (Tee-fur) book "Sex Is Not a Natural Act: and Other Essays."(Westview) was published in 1995, and has since come out in paperback. In the book she looks at our society''s anxieties and ignorances towards sex. She also questions what is "normal" sex and how people are to know how to have sex if no one talks about it. . TIEFER received a Ph.D. in physiological psychology with a dissertation on hormones and mating behavior of rats. But TIEFER came to realize she knew nothing of the social norms of sexuality and questoned how sexual norms evolved. She re-specialized in clinical psychology and became a sex researcher, sex therapist and an Associate Professor of Urology and Psychiatry at the Montefoire Medical Center in New York City. Tiefer has also been a sex columnist for the New York Daily News. (REBROADCAST from 2/8/95)REV. 2: T.V. critic DAVID BIANCULLI on the Super Bowl hype, and the special episode of "Friends" which airs after the Super Bowl.