Along with Larry Flynt for President, another documentary at the Tribeca Festival takes a look at a flamboyant advocate for sexual freedom, although one with a completely different point of view and approach: Lady Boss: The Jackie Collins Story, a playful, penetrating portrait of the prolific best-selling author and Hollywood insider. Programmed in its Spotlight Documentary section, the festival has served up the equivalent of a juicy and thoughtful beach read.

The author’s older sister, actress Joan Collins, and her three daughters and a network of close friends—all of whom believe they were the writer’s best friend—freely dish the dirt. With qualifiers, they lay out Jackie’s strengths and contradictions. (It seems no one was a fan of a boyfriend that Jackie turned to after the death of her second husband and chief cheerleader, Oscar Lerman.) Even her longtime literary agent, Morton Janklow, describes his client as not an eloquent writer but a great storyteller.

When Joan’s acting career was on the rise at 20th Century Fox in the mid-1950s, 16-year-old Jackie joined her for the summer in Los Angeles, going out with her on the town—the teen observed that Marilyn Monroe’s walk “could make a revolving door look static.” In one talking-head segment, Joan confirms to director Laura Fairrie the oft-told tale that her sister lost her virginity to Marlon Brando at a Hollywood party.

The younger Collins attempts to follow her sister in the footlights, her reinvention through plastic surgery, and her turbulent first marriage could be the opening chapters for any of her future novels. As a writer, she was self-taught (her first success was 1968’s The World Is Full of Married Men) and a tireless self-promoter—big hair, shoulder pads, and all. Her formula for her books’ huge sales typically included a beautiful and strong-willed female protagonist overcoming calamities to outwit doubters, as well as having great acrobatic sex in the most rarified settings.

Now, to get to the chapter that would have been dog-eared had the documentary been a book instead: Fairrie brings up and then pours water on the idea of a heated rivalry between the two sisters, although she points to at least some awkwardness between them in the ’80s and ’90s, when both were international media stars. Joan admits their relationship “was slightly cool” and kind of difficult at the time; Jackie was not getting along with Joan’s then-husband and a later boyfriend. The sisters’ former sister-in-law, Hazel Collins, shrugs off the sibling tension: “I came from the fashion world, so I’m used to bitches.”

For film buffs, there are clips of Joan in The Stud, the 1978 clothing-optional adaptation of her sister’s 1969 novel, which co-starred Oliver Tobias, who, Joan dryly notes, “thought he was the Second Coming.” It was meant as a vehicle for the actress during a dry spell of roles, though her career wouldn’t really reignite until she stirred trouble on the ’80s soap Dynasty. A young Sandra Bullock makes a brief appearance in a glimpse from the 1990 TV miniseries Lucky Chances, based on one of the many books featuring the author’s heroine and alter ego—as her friends posit—Lucky Santangelo. (The documentary takes its title from the 1990 installment of Lucky’s adventures.)

Lady Boss: The Jackie Collins Story had its world premiere at the Tribeca Festival and will begin airing on CNN June 27.