A year in the life of a woman who trailblazed for today's female comics and remains as driven, hard-working and career-focused as ever.

Seen at age 75, with more than four decades in showbiz behind her, the subject of “Joan Rivers: A Piece of Work” is hardly resting on her laurels — in fact, it’s hard to imagine her resting at all. Parting from the social-justice themes of their prior docs, co-directors Ricki Stern and Annie Sundberg observe a year in the life of a woman who trailblazed for today’s female comics and remains as driven, hard-working and career-focused as ever. Mixing hilarious standup footage with admiring if not exactly cuddlesome behind-the-scenes glimpses, the pic is a shoo-in for cable sales.

We see brief glimpses of Rivers’ formative successes — notably on “The Tonight Show,” where Johnny Carson decreed on-air that she’d be a star, leading to umpteen guest and guest-host appearances. (Years later, however, Carson considered it a betrayal when she got her own ill-fated Fox chatshow, never speaking to or hiring her again.) But the focus here is on current everyday operations, which demonstrate how much effort it takes to stay on top (or even in contention), no matter how lofty your track record or Q rating.

Rivers is acutely aware of her status in the food chain at any moment in time. Suffering a relative lull at the pic’s start, she’ll “do anything” to keep working, whether it’s performing club gigs or at suburban Midwest halls, or hawking jewelry on QVC. An autobiographical stage play on which she’s pinned great hopes triumphs in Edinburgh, but tepid critical response in London quashes its Broadway prospects. However, a potentially humiliating season as contestant on “Celebrity Apprentice” ends in victory, once again making her a hot commodity.

Beyond the lady herself, major interviewees include daughter Melissa, with whom she has a complex but close relationship, and her loyal staff, though the manager she’s known for decades finally has to be fired for his frequent, unexplained disappearances.

Rivers’ workaholism and insecurities (which don’t prevent her from being nearly as brash offstage as she is on) don’t necessarily make the comedy biz look like a barrel of laughs. But she’s reliably funny in performance, with the live ones considerably more profane than her TV appearances.

Well-tuned package moves at a smart pace; the pic won an editing award at Sundance.

Joan Rivers: A Piece of Work

Production

A Break Thru Films production. Produced by Ricki Stern, Seth Keal, Annie Sundberg. Executive producer, Stern. Directed by Ricki Stern, Annie Sundberg. Screenplay, Stern.

Crew

Camera (color, HD), Charles Miller; editor, Penelope Falk; music, Paul Brill; sound, Seth Keal. Reviewed at Sundance Film Festival (competing), Jan. 26, 2010. Running time: 84 MIN.

With

Joan Rivers, Jocelyn Pickett, Billy Sammeth, Larry Thompson, Kathy Griffin, Melisa Rivers, Don Rickles.

Filed Under:

Follow @Variety on Twitter for breaking news, reviews and more