BEFORE JOAN CRAWFORD died in 1976, she cut both of her adopted children out of her will. One of these children, Christina Crawford, vowed to take revenge on her mother. So she wrote a book called Mommie Dearest, which explains what a drag it was to grow up as the daughter of one of America's all-time favorite movie stars. Revenge in this case must have been particularly sweet, for not only was the book a bestseller, but Paramount Pictures also decided to make a movie out of it.

As far as the movie is concerned, though, Christina's revenge comes at the audience's expense. Mommie Dearest is a ridiculous, insulting and ultimately boring film. Perhaps Joan Crawford was not a good mother; maybe she did take out a lot of her frustrations on her daughter, and she no doubt drank too much. But do we really want this mess laid out in graphic detail? Do we want to see Joan spanking Christina? Do we want to witness petty family squabbles? Mommie Dearest comes off as little more than the private vendetta it is.

There is no real plot to this travelogue of the Crawfords' ups and downs during Joan's career. The problem is, we rarely get out of the family's house. We never see Joan filming a movie or interacting with other movie stars. Instead, we sit around the living room watching Christina get yelled at. A history of Joan's career might have been worthwhile; she was an interesting character. Her daughter is not. But since Christina wrote the book, she's what we get. The other Crawford child, Christopher, is something of a non-character in Mommie Dearest. He appears briefly in the beginning as a little kid, only to disappear until his mother's funeral.

FAYE DUNAWAY, who plays Joan, cannot be blamed for the failure of this film. She is a fine actress, and the work she invested to perfect her Joan Crawford imitation is evident throughout. Her recreation of Crawford's seductive, almost sneer-like frown is remarkable. And the make-up artists deserve credit, too, for Dunaway looks as well as acts the part. Both Diana Scarwid and Mara Hobel, who play Christina as a child and as an adult, respectively, turn in good performances. There is no problem with the acting in Mommie Dearest. The flaw is the absolute lack of substance in the script and the plot.

Director Frank Perry seems content simply to let Joan and Christina rant and rave at each other, and he makes few attempts to explain Joan's complex characters or to dig beneath the disputes for the real reasons for Crawford's mistreatment of her daughter. When the scenes roll around in which Joan is nice to her daughter, we are only further confused. The relationship between Christina and Joan is shown through a series of vignettes which take place over a span of 30 years, but these scenes are only loosely strung together. They argue here, they argue there, time passes and no conclusions are reached. Mommie Dearest, while attempting to pass itself off as a serious documentary, is little more than a limp soap opera.

It's too bad that Christina could not have resisted taking revenge on her mother, and it's too bad to see Joan Crawford posthumously dragged through the mud. Christina's attempt to cash in on her mother's problems shows very little class on her part. It would have been much better all around if this movie were never made.