Blasphemy, pornography and endangering the security of the State were all reasons for South African censors to ban books. By the 1970s as many as 20,000 books had been banned.
A line in a book like “Oh God I’m tired!” was considered blasphemy. Even a four-letter word might be considered pornographic.
A simple joke about the South African police might be seen as endangering the security of the State.