World War III is a common futuristic event in novels, film and all forms of media today. But in between World War I and World War II, were there any pieces of fiction written about a potential Second Great War in the same style that World War III is written about today?
Indeed. Even before World War I there was a genre of "[Invasion literature] (http://en.wikipedia.org/wiki/Invasion_literature)" featuring hypothetical invasions of e.g. Britain, the USA or Japan. Some of the best known are the works of H G Wells, who wrote [The War In The Air] (http://en.wikipedia.org/wiki/The_War_in_the_Air) and [The World Set Free] (http://en.wikipedia.org/wiki/The_World_Set_Free) before World War I, and in [The Shape of Things to Come] (http://en.wikipedia.org/wiki/The_Shape_of_Things_to_Come) in 1933 predicted a world war in 1940, started by a clash between Germany and Poland.
The military theorist Giulio Douhet, one of the major advocates of strategic bombing, also illustrated his theories in the fictional "The War of 19--", which can be found at the end of [this translation of The Command of The Air] (http://permanent.access.gpo.gov/airforcehistory/www.airforcehistory.hq.af.mil/Publications/fulltext/command_of_the_air.pdf).
In 1925, Hector Bywater published The Great Pacific War which predicted a Japanese-American war. The novel did not predict a surprise attack on Pearl Harbor, contrary to some popular claims. But the Japanese and Americans do employ naval airpower.
One work that springs to mind straight away is Things To Come, A British sci-fi film from 1936. It predicted a global conflict lasting several decades, which would start in 1940.