Erskine Childers

The Riddle of the Sands, published in 1903, sends two Englishmen yachting among the Frisian sandbanks and has them stumble on a plan for the invasion of England, and it is routinely named as the first modern spy novel. Childers wrote it partly as an argument for taking North Sea defence seriously, and the Admiralty took the point. He clerked at the House of Commons, fought in the Boer War, and in 1914 sailed his own yacht into Howth carrying rifles for the Irish Volunteers. He went into the Royal Navy for the next war, then took the republican side against the Anglo-Irish Treaty, and the Free State put him to death by firing squad in November 1922. His son of the same name became President of Ireland.