In South Africa the source of misery is always the same: apartheid.

"Age of Iron," the new novel by veteran South African writer J.M. Coetzee, continues the tale of woe. Set in contemporary Cape Town, it's the story of an elderly woman dying of cancer whose final days are clouded by the kinds of chaos and violence she has always lamented but never had to contend with in the larger society around her."Mrs. Curren" - her first name is never given - had been a classics professor at the local university, a woman whose position had always insulated her from the system's harsher realities. Now that she's dying, however, she is suddenly helpless to keep at bay all the trouble that comes knocking at the door of the big, crumbling house she lives in, all alone, in one of the better parts of town.

Among those who show up is a derelict named Vercueil, who moves into her woodshed early on and will not be dislodged. In large part the novel becomes the story of the developing relationship between Mrs. Curren and the homeless, alcoholic Vercueil. Is he the Angel of Death come to speed her on her way? Or is he, maybe, an angel of a different kind, come to elevate her in her suffering? We never quite know. By novel's end, however, he has become her "shadow husband."

Someone else who arrives at her doorstep is a teenaged black activist, the friend of her former housekeeper's son. It is this boy, never named, who eventually involves her in the underside of Cape Town life, a world of violence, repression and accelerating racial struggle.

Before it's over Mrs. Curren will witness the burning of a black township, come upon the bullet-shattered body of her servant's son and finally have to stand aside as the security police assault her own home in order to blast out the young militant.

The entire novel is cast in the form of an extended letter to Mrs. Curren's only child, a daughter, who long ago emigrated to America. And one of the problems with the book is that Mrs. Curren is the only fully drawn character in it. Everyone else is shadowy, withdrawn, insubstantial - even Vercueil.

The result is that everything seems to be seen through a curtain, a fog of language and abstraction, since there's really no one around of equal stature for her to bounce off of.

Still, it's a letter - and a novel - worth reading, if for no other reason than its sheer six-o'clock-news topicality. The days of rage continue in South Africa, and Coetzee, with this and earlier novels such as "Waiting for the Barbarians" and "The Life and Times of Michael K.," continues to be a valuable witness.