Tet Offensive

Tet Offensive was a novel by time-traveler Michelle Gordian (under her penname of "Mark Gordian"). It was based on the Vietnam War, but published in the early 1950s, at a time when most Americans had never even heard of Vietnam. It was set in the future, and depicted a war gone horribly wrong. Jim McGregor, the novel's editor, had initially thought about rejecting it, fearing that readers would find it unbelieveable. However, he realized that it was internally consistent, and so published it.