What do they think we know?

Despite being set in the future and, more often than not, outside our solar system, science fiction manifests and sometimes deliberately addresses contemporary concerns. In the novel The Forever War (1974) by Joe Haldeman, soldiers from Earth return to their home planet after fighting a distant war against an alien enemy. Because of time dilation, the soldiers arrive 30 years after they set off. The changes in human society that had taken place in their absence are alienating to the returnees, in a way that echoes the experiences of soldiers, like Haldeman, who came home after serving in the Vietnam War.