The Royal Navy is about to pay a high price for its neglect of airpower ...
Front cover of E. F. Spanner, The Broken Trident (London: E. F. Spanner, 1929).
I just like this picture for some reason. Spanner was a retired naval architect who evidently had at least one bee in his bonnet, for he wrote about half a dozen books on various aviation matters (including the inadvisability of the government's Imperial airship scheme -- well, he was right about that), and what's more, he published them all himself! The Broken Trident was originally published in 1926, and the cover above is from the 1929 "cheap edition" (price: 2/6), so either the first edition sold enough to warrant going down market, or probably more likely, he wanted to get his message out to a wider audience. There was also a German edition (1927), which I'm sure would have sold relatively well, given the effortless ease with which, in the novel, a supposedly downtrodden Germany bests a smug and complacent Britain.
Update: I was looking at another book of Spanner's today, Armaments and the Non-combatant: To the 'Front-line' Troops of the Future (London: Williams and Norgate, 1927), which is a non-fictional rendition of many of the ideas in The Broken Trident. So obviously not all of his books were self-published (as I stated above), at least the first editions, contrary to what the cover of The Broken Trident suggests. In Armaments and the Non-combatant, Spanner notes (p. 295) that he wrote The Broken Trident (among other books) as a novel because 'in that form I thought it easy to present facts and probabilities so that they might gain the attention of technical men of all shades of thought and also the attention of ''the man in the street''', and appends excerpts from its favourable reviews. The title page also notes that he's the 'Inventor of the Duct Keel system of Ship Construction, the "Soft-ended Ship" system of Bow Construction, the "Spanner" Strain Indicator, etc'.