Ever looked at Joan Rivers and wondered, "why is she still around?" You'll get your answer in the new tell-most, Joan-sanctioned documentary "Joan Rivers: A Piece of Work." It's because the woman never, ever stops working.

Ever looked at Joan Rivers and wondered, "why is she still around?" You'll get your answer in the new tell-most, Joan-sanctioned documentary "Joan Rivers: A Piece of Work." It's because the woman never, ever stops working.

For as far back as I can remember, Rivers has been on the low end of the D-list celebrity list, chatting up celebrities on the red carpet and shilling her jewelry on QVC. I knew who she was but little about how she got there.

After a career-high gig as Johnny Carson's permanent "Tonight Show" guest host, the foul-mouthed comedienne went on a downward spiral that involved a disastrous late-night Fox show, her husband's suicide and getting blacklisted from NBC.

These days, the 77-year-old's main objective is avoiding blank days on her calendar (it's hard to tell if her motive is retaining her celebrity status or just financing her opulent lifestyle), so she claws and scratches for any job she can get. Stand-up gig in Wisconsin, spokeswoman for penile-enhancement products - she'll do anything.

Rivers also understands that she's usually the butt of the joke, even if she's not happy about it. Watching her utter terror as she walks into her own Comedy Central roast is a reminder that underneath that scrappy exterior is a lot of sadness.

And even if "A Piece of Work" doesn't make you like her, it'll at least make you respect her.