It's a matter of some dispute whether Roman Polanski's letter to the darker side of the romantic impulse--a French-English production made in 1992--represents him at his best or worst (I'd say the former), but there's little question that this is his most emotionally complex movie to date. With its American, English, and French characters representing the three cultures Polanski has known since he left Poland, it's also quite possibly his most personal film--and certainly his most self-critical. The major focus of the plot, told in flashbacks, is the perverse relationship that develops in Paris between a failed, well-to-do American writer (Peter Coyote) who becomes crippled and a young French dancer (Emmanuelle Seigner); their encounter with a British couple (Hugh Grant and Kristin Scott-Thomas) on a luxury liner on the Black Sea forms the present-tense story. This uneasy combination of comedy and tragedy, frank pornography and caustic antipornography, sexual fun and games and mental cruelty doesn't allow the audience a comfortably detached viewpoint from which to judge the proceedings. Chances are you'll either love it or despise it. Music Box, Friday through Thursday, April 15 through 21.