Novel for foreigners who want to understand the Afrikaner; A Dry White Season, by Andre Brink. New York: William Morrow & Co. $10.95.

Andre Brink's latest novel about his own people, the ruling Afrikaners of South Africa, preaches opposition to apartheid in the unadorned fatalistic style that Afrikaners believe is frank and honest.

"A Dry White Season" was banned by the South African government, which fears Brink's type of "subversion" even more than that of white novelists such as Nadine Gordimer. But before the banning, which was lifted recently, Brink managed privately to print 3,000 copies and to distribute them in the Afrikaner "underground."

Few novels will speak to the Afrikaner -- or to foreigners who want to understand the Afrikaner -- as well as this one. By its very plainness it could lead some believers in apartheid to ask questions.

Brink's protagonists, Ben Du Toit, is a typical Afrikaner -- a middle-aged, married schoolteacher and father of three who accepts the apartheid system, who has never entertained a black in his home, who has never set foot in a black city such as Soweto. When a black cleaning man in Du Toit's school is killed in the hands of the security police, Du Toit is slowly sucked into opposition to the system. But he is driven by a sense of justice -- a common motive for many white South Africans' opposition apartheid -- rather than by any deep human relationship.

In fact, the personal relationships in the book are largely one-dimensional. The reader senses that Du Toit cannot relate deeply to any black, and his emotional breakthrough comes with his love for a young, white, liberal journalist -- something of a scandal in Afrikaner society. This may have been deliberate: Few whites would accept anything more scandalous, and Brink has written a novel intended to have political impact.

For one who has lived in South Africa and reported on that country's society, "A Dry White Season" seems not to be fiction at all -- but rather straight facts with names changed and characters merged to protect both the guilty and the innocent.

The first two-thirds of the book is almost Calvinistically bloodless, but the action nevertheless carries the reader forward. Du Toit is killed, apparently by security police, and exploring the why and how of his death lends force to the plot, which is the book's great strength.

Brink handles his material with skill, interrupting the flow of the narrative only occasionally with moralizing. But the novel is slightly marred by a sense that Du Toit is a nebulous character (a kind of Everyafrikaner, rather than a specific individual), and it also is jarred by the stylistically awkward inserts from Du Toit's diary.

Black South Africans may deem this a "white book," an understatement of the South African situation. But given the pressures of Afrikaner society and the security police, Brink's decision to speak out required an exemplary kind of bravery.