The invasion novel was a popular form of literature from the 1870s until 1914. It was especially popular in England, where the invaders were usually Germans. In Asia the Russians were most often the invaders, in Australia it was Asian aggressors, while America usually feared Germany. Hundreds of these works were published around the world, and collectively this genre provided the foundation for the emergence of spy thrillers and science fiction.
As tensions were rising in Europe, with increasing economic competition, sparring over overseas colonies, and rearmament in Germany and Britain, English writers found that they could easily sell books telling exciting stories about foreign invasions, usually from Germany.
This genre is often considered to have start with the publication of The Battle of Dorking by George Tomkyns Chesney in 1871. Published just after the Franco-Prussian War, it told of an unnamed German-speaking country with superior forces invading and defeating England. More cheerful tales were common as well, with works like Erskine Childers' Riddle of the Sands (1903) telling of two Englishmen on a boating trip who discover a secret German plan to build a fleet of invasion barges. They save the day, but the epilogue warns that the British government has not been protecting against exactly this sort of invasion.
Riddle of the Sands is credited with helping shape the genre of spy novels, and the prolific invasion author William Le Queux's character Duckworth Drew may have been the inspiration for James Bond. H.G. Wells' The War of the Worlds (1898) and The War in the Air (1907) helped popularize science fiction. While dramatic invasions are still a common literary theme, it is no longer a clearly defined, self-standing genre, and is not generally recognized on the shelves of today's bookstores.