Final answer:
Alan Paton is the writer known for works that dealt with the effects of apartheid, notably through his famous novel 'Cry, the Beloved Country' which addressed the social and racial issues in South Africa.
Step-by-step explanation:
The writer known for works that dealt with the effects of apartheid on their country is Alan Paton. While Nelson Mandela was a pivotal anti-apartheid figure and the first Black president of South Africa, his literary contributions do not focus on apartheid in the same fictional sense as Alan Paton's work. Paton's most famous novel, Cry, the Beloved Country, published in 1948, is revered for its poignant exploration of the deep social and racial divides in South Africa during apartheid.
Although J.M. Coetzee and Athol Fugard have also addressed apartheid in their works, Paton's novel was one of the earliest to gain international attention. It provided a compassionate yet unflinching look at South Africa's racial injustices from multiple perspectives, showing the universal humanity threatened by such a system. This has made Cry, the Beloved Country a cornerstone in apartheid-related literature, frequently studied for both its literary merit and its social commentary.