We come to understand too, something of the mechanics that go into the making of one single concert on one single night to one single audience. What indeed has made this night memorable for her?
We are recording and preserving a memory. And that is what's "special" about it. The insight into what goes into every live performance Liza ever gives should make it all illuminating, stimulating and theatrical. How well she does what she does should make it all entertaining and truthful.
The truth is what makes this special a documentary.