There’s no shortage of material out there designed to pry into the personal lives of famous figures. There’s even a whole battalion of individuals who are famous for no other reason than their willingness, even needy enthusiasm, to have cameras following their every movement. In this culture of overdisclosure, it’s reasonable to wonder if a documentary that does little more than train a camera on a celebrity as she goes about her daily life can still be revelatory. Of course, that question is also indicative of the forgetfulness instilled by the saturation presence of supposedly intimate reality programming which replaces intelligent, capable filmmaking with hostile manipulation. It’s easy to lose sight of the not-so-minor detail that the difference between crass voyeurism and worthwhile insight resides in the capability of the directing job. Naturally, a fascinating subject helps, but it’s up to the filmmakers to demonstrate why the subject is fascinating.

Directors Ricki Stern and Anne Sundberg make their case very effectively with the new documentary Joan Rivers: A Piece of Work. The veteran comedienne agreed to have the filmmakers track her for about a year, catching her as she celebrates her seventy-fifth birthday, relents to being roasted on Comedy Central, appears as a contestant on Celebrity Apprentice, and generally tries to keep her head above water in the brutal seas of the entertainment industry. Her ongoing struggles demonstrate that the ordering of words in the term “show business” is just another case of the billing being off. Business is clearly predominant. Rivers is, as she notes at one point, her own industry with a small, dedicated band of employees and a need to constantly work the phones and play every angle available to make sure her date book is properly filled. The film makes the case that Rivers is an undervalued trailblazer, but what’s most notable is the way it pulls away the glittery shell of her chosen field to expose the grinding gears underneath.

By its very nature, the film is episodic. A year-in-the-life approach probably isn’t going to cohere to the niceties of a clean narrative structure. Stern and Sundberg sidestep that little issue by expertly finding the trajectories within individual sequences. When Rivers plays a gig at a Wisconsin casino, a joke she makes involving Helen Keller is heckled by an audience member who takes umbrage because he has a deaf son. Onstage, Rivers is livid over the interruption, and is still dwelling on it immediately after her set. It’s a sharp enough moment on its own, but made more interesting when her stance softens as she discusses it with a fan backstage and then turns into outright sympathy for the man when she’s being escorted to her car at the end of the night. There’s a lot that can learned about Rivers in this sequence–the potency of her survival instinct, the internal conflict between her preference for raunchy, potentially offensive jokes and her capacity for caring about others’ feelings, her helpless need to dwell on things, especially slights–and Stern and Sundberg efficiently pull together every telling bit. This is an example of how the film crosses over from trumpeting that Joan Rivers has endured to explicating precisely how that has happened. In doing so, the film demonstrates its value above other contributions to our culture’s fame-obsessed din.