Julianne Moore has already tackled drug addicts, tough cookies, sexual free spirits and desperate housewives.

Now, in "Savage Grace," which opened Friday at the Lagoon in Minneapolis, she takes on Barbara Baekeland, a character so over-the-top nuts that, were she to show up on Wisteria Lane, she would probably cause Susan, Bree and Gabrielle to lock their doors.

Barbara -- around whom "Grace" revolves -- was a real desperate housewife. Unhappily married to Brooks Baekeland, the heir of the Baekeland plastics fortune, she schemed, preened, traveled the world and bore a son, Tony, to whom she was rather unusually devoted. She ended up stabbed to death in 1972.

"She was boundary-less," Moore said. "Barbara needed to be looked at and appraised, to be the central figure, and yet she was not without her own degree of interest and compassion."

By most accounts, Barbara was often the life of a party, but could just as often leave members of the Eastern seaboard upper crust shaking their heads the moment the door shut behind her. She slept with her son, ostensibly to "cure" his homosexuality.

"The most difficult thing was to bring her to a completely human scale," Moore said. "This person who had done these things that were completely out of control, maybe even monstrous. How do you bring that into a room? That was always the challenge."

Howard Rodman's script landed on Moore's desk nearly six years ago, shortly after the birth of daughter Liv, her second child with director Bart Freundlich ("The Myth of Fingerprints"). Moore immediately told producer Christine Vachon of her interest, but "Savage Grace" took several years to get financing.

"It was a true story, and it really blew me away," she said. "It's an unbelievable, almost Greek tragedy, endlessly interesting."

The physical resemblance between the two women is notable, but that's hardly the reason that producers and director Tom Kalin went after Moore.

"She's incredibly gifted at finding moments of behavior that express and suggest the deeper psychological contours of a character," he said. "She's intuitive, not intellectual -- though I couldn't think of a more bright person -- and she's brave enough not to judge any of the characters she's playing."

That quality is probably to her benefit. Moore, as previously noted, has played rather extreme types before (including her characters in "Magnolia," "Freedomland" and "The Hours"). How deeply, then, does the four-time Oscar-nominated actress crawl into someone like "boundary-less" Barbara's skin?

"Not that deeply," says Moore, 47, with a laugh. "I have a family and two small children. When I go home with the kids, that's how it is. I don't have the luxury of dragging [my character] around."

Earlier this summer, Moore was in Cannes promoting the upcoming film "Blindness," based on the novel by José Saramago and directed by Fernando Meirelles.

She has appeared in three of her husband's movies, and their children -- ages 10 and 6 -- have had cameos in "Trust the Man" and "Blindness."

"They come on set with me, and I think they know about acting and stories and film, but they don't really have any interest," Moore said. "They're very interested in what their parents do, period, and I think that's a healthy way to be."

They haven't seen most of their mom's movies. Unlike Barbara Baekeland, the Freundlich/Moore household has boundaries.