Rather than try to capture its central storyline and authorial intent myself (read: cannot do so), here is something lifted from Amazon which makes a fine job of doing so (although I'm not necessarily saying she gets it fully right...). All I will add is that the quality of Coetzee's writing is truly outstanding.
So, over to you, Rachel....
Disgrace takes as its complex central character 52-year-old English professor David Lurie whose preoccupation with Romantic poetry - and romancing his students - threatens to turn him into a "a moral dinosaur". Called to account by the University for a passionate but brief affair with a student who is ambivalent about his embraces, David refuses to apologise, drawing on poetry before what he regards as political correctness in his claim that his "case rests on the rights of desire." Seeking refuge with his quietly progressive daughter Lucie on her isolated small holding, David finds that the violent dilemmas of the new South Africa are inescapable when the tentative emotional truce between errant father and daughter is ripped apart by a traumatic event that forces Lucie to an appalling disgrace. Pitching the moral code of political correctness against the values of Romantic poetry in its evocation of personal relationships, this novel is skillful - almost cunning - in its exploration of David's refusal to be accountable and his daughter's determination to make her entire life a process of accountability. Their personal dilemmas cast increasingly foreshortened shadows against the rising concerns of the emancipated community, and become a subtle metaphor for the historical unaccountability of one culture to another.
The ecstatic critical reception with which Disgrace has been received has insisted that its excellence lies in its ability to encompass the universality of the human condition. Nothing could be farther from the truth, or do the novel - and its author - a greater disservice. The real brilliance of this stylish book lies in its ability to capture and render accountable - without preaching - the specific universality of the condition of whiteness and white consciousness. Disgrace is foremost a confrontation with history that few writers would have the resources to sustain. Coetzee's vision is unforgiving--but not bleak. Against the self-piteous complaints of all declining cultures and communities who bemoan the loss of privileges that were never theirs to take, Coetzee's vision of an unredeemed white consciousness holds out - to those who reach towards an understanding of their position in history by starting again, with nothing - the possibility of "a moderate bliss." --Rachel Holmes