What made it that way _ that's where deeper fascination lies.

Especially when it's as stranger-than-fiction bizarre as Little Edie, Big Edie and their rambling wreck of a Hamptons manse immortalized as the title character of the cult documentary "Grey Gardens."

Its cinema-verite portrait of mother-and-daughter grande dame eccentrics, filmed by Albert and David Maysles, has only soared in fame and fandom since its 1975 premiere. Many of the film's most ardent aficionados weren't even born when this camp-courting tale of faded wealth and exuberant behavior initially achieved renown.

That was back in pop culture's original "reality" era, when TV was learning to eavesdrop ... when PBS' mid-'70s shocker "An American Family" kept cameras rolling as an "average" married couple unraveled toward divorce.

Private behavior on public display is commonplace now. But it was astounding at the time. And despite today's self-revelation saturation _ or perhaps because of it _ "Grey Gardens" is on its second wind. The co-dependent recriminations of its aging mother and daughter, isolated in a filth-infested country house, have recaptured the public imagination. There's been a Broadway musical, fan sites on the Web and now a new HBO movie expanding on the Maysles' actuality.

This "Grey Gardens" (Saturday at 8 p.m. on HBO) boasts immersive performances by Jessica Lange, as the larger-than-life mother keeping her daughter close, and Drew Barrymore, as the flamboyant yearner idling in her gilded cage. HBO's saga looks back beyond the documentary to chart 40 years of the pair's past, to reveal how two charmed lives _ mother Edie was aunt to Jacqueline Kennedy; daughter Edie was her cousin _ devolved into seclusion and squalor.

They radiated amusement, too. Both mother Edith Ewing Bouvier Beale (1895-1977) and daughter Edith Bouvier Beale (1917-2002) had wanted to be showgirls, at a time that wasn't proper for their social status. Thwarted in public, they performed in private, initially for others, and finally for each other. "Well, mother and I are very entertaining," Barrymore's Little Edie agrees when the Maysles propose filming their daily songs and squabbles inside their decaying house on East Hampton's Lily Pond Lane.

Three decades later, the writer-director of HBO's movie, Michael Sucsy, would come to that same door, after the once-grand home had been restored by new owners Ben Bradlee and Sally Quinn of The Washington Post. "It was a rainy day, and I told (their tenants) who I was, and they let me in, and were so kind," recalls Sucsy, at 36 one of those latter-day devotees barely born when the Maysles shot there.

But Sucsy (pronounced Soo-see) "grew up in Long Island in the summers," he recalls by phone, in a family long established on the East End (although he spent most of his youth in Hartford). "We had a house for many years in Hampton Bays, and still own one in Quogue," he says. "It's not what attracted me to the story, but it just made me feel comfortable in that environment, and understand it all."

Sucsy had been headed for a charmed life himself, studying foreign service before opting out to become a director of commercials. When he saw the Maysles film in its 2001 DVD release, he was blindsided by its very personal, yet universal, impact.

"What really drew me in was who they were, and their personalities. They were full of contradictions _ so strong, and then so vulnerable." Seeing these women charge at life head-on, after being deflected from their desires, he recognized: "Some people fulfill the expectations that are set out for them, and other people realize at some point their destiny isn't really in line with that. The inherent conflict is within, versus coming from outside of you."

Sucsy went to work the day after he saw the documentary. Researching apart from the musical team, and from Maysles Films, Sucsy approached the Beales' heirs (Big Edie's grandchildren), snagging the rights to their life stories, along with Little Edie's papers, as a basis for his script. "I wrote it not needing the documentary, because I didn't want my project to hinge on something I didn't have." He later joined forces with producer Rachael Horovitz, who'd pursued a similar project with Albert Maysles. (David Maysles died in 1987.) Parts of their HBO movie do re-create moments from the documentary, as well as its shooting.

But this dramatized "Grey Gardens" might better be considered the earlier film's back story. Sucsy reveals the younger Beale women as 1930s Manhattan socialites and Hamptons aristocracy. As their lives progress and money dwindles, as other people retreat from their eccentricities, the pair's universe reduces to their symbiotic essence _ iconoclastic, gutsy, determined to stay joyful even as they employ bickering for daily amusement. The Edies' spirits remain unbroken.

So much so that their twisted ...