When I was in 7th grade(back in 1977), I was asked to read the novel that this was based on as part of my English class studies. I can remember being very touched by it and excited when a TV version came out a year later.
Kristy McNichol was a popular TV actress when this film was produced and was already playing a daughter in a dysfunctional family on the hit TV series "Family". It was clear that she had the range and ability to pull off this part. I recall her as being a bit "stiff" at times, but over all she does a good job. She carries the movie well.
Esther Rolle is fantastic as the domestic who appears to be the only one in the household that seems to truly care for her. Barbara Barrie as the somewhat frightened and slightly neurotic mother is also good, as is young Robin Lively (who would eventually appear as the black widow Lana Milford in "Twin Peaks")as the sweet younger sister who seems to be the focus of the parent's affection. Bruce Davidson is also appropriately appealing as the German soldier of the title
The best performance, however, belongs to Michael Constantine. It is truly powerful and merited more recognition than it got at the time. The bitterness and coldness he expresses makes the scenes in which he appears difficult to watch, but makes it much easier to understand the quiet desperation of the rejected daughter. Constantine gives everything the right intensity and seems to have a good understanding of the underlying psychological motivations.
The film differs from the book only in some small ways. It is wonderful and inspiring to watch, and I hope that it gets released again on to video or DVD.