The subject area of invasion scare and future war novels can be extended to cover a vast array of novels including many in the science fiction genre. For the purposes of this site I have set boundaries as follows:
Date: novels published between 1870 and 1914.
Some later examples are included where they relate to the pre-war situation or have relevant continuity from pre-war novels.
Origin: novels first published in Britain.
The main scope is novels written in English and published in Britain. However, there is coverage of, primarily, French and German novels and stories from the period. There are occasional examples in other languages.
Some books published outside Britain relating to wars or invasion of non-European countries are included as Overseas Wars & Invasions.
Contemporary or near-future plot.
Usually the novels are looking into the near future. My guideline here is that they are set in what is recognisably the culture, geography and political structures of the time of writing. So, for example, Herman Lang’s 1859 The Air Battle is excluded, being set in the far future (around 6900 AD).
Dealing with human war.
Novels that deal with alien invasion and wars, while a respectable sub-genre within science-fiction, are excluded. So, for example, H.G. Wells’s The Land Ironclads (1903) is included while The War of the Worlds (1898) is not.
I have included works that are speculative regarding the technologies of future war where these are grounded in emerging technologies of the time rather than being pure fantasy.
Here, I have tried to limit the scope to works that relate to the main political / geographic tensions of the then contemporary world rather than stories which happen to include a spy or spying but have no real relationship to the socio-political issues of the day.