Sixth Column
Warning: Plot details follow.
Sixth Column, also published under the title The Day After Tomorrow, is a 1949 science fiction novel by Robert Heinlein, set in a United States that has been conquered by a foreign invader. It centers on the activites of a research lab hidden in the Colorado mountains, which is is the last remaining outpost of the United States Army after its defeat by the Pan-Asians. The conquerors had absorbed the Soviets after an attack by them and had gone on to amalgamate India as well. The invaders are depicted as ruthless and cruel - for example, they crush an abortive rebellion by killing 150,000 American civilians as punishment.
The book is notable for its frank and controversial portrayal of racism. The Pan-Asian conquerors regard themselves as a chosen people predestined to rule over lesser races, and they refer to white people as slaves. "Three things only do slaves require: work, food, and their religion." They require outward signs of respect, such as jumping promptly into the gutter when a member of the chosen race walks by, and the slightest hesitation to show the prescribed courtesies earns a swagger stick across the face. One character is Frank Mitsui, a hunted man mourning the murder of his wife and children by the invaders because "they did not fit" in the new PanAsiatic racial order. The Americans in the novel respond to their conquerors's racism by often referring to them in unflattering terms, such as flat face, slanties (a derisive reference to the epicanthal folds typical of Asian genetics), and monkey boys.
Some people view both Sixth Column and Farnham's Freehold, another novel by Heinlein, as proof that Heinlein is a racist. A more accurate statement would be that Heinlein made strong philosophical points about racism in these two works, and that some people who disagree resort to attacking the author's reputation rather than answering his arguments. (Moreover, in the case of Sixth Column, the original story idea was developed by John W. Campbell, not by Heinlein himself.)
On the other hand, some commentators have claimed that the strongly hierarchical and anti-individualistic "Bug" society in Starship Troopers is based on World War II-era Japan. Then, too, Heinlein's hero E.C. "Oscar" Gordon, in Glory Road, makes unflattering comments about Asians (including the Vietnamese, whose women he claims to find sexually unattractive because they are allegedly small and childlike). Of course it will always be possible to argue that the views of a character do not necessarily reflect those of the author, and Heinlein did include sympathetic Asian characters in his later works (e.g. "Tiger" Kondo in The Cat Who Walks Through Walls -- a cameo appearance by Yoji Kondo, a NASA scientist of Heinlein's acquaintance who also edited the tribute volume Requiem).