The Riddle of the Sands: A Record of Secret Service is a 1903 novel by Erskine Childers. | Carruthers, a minor official in the Foreign Office, is contacted by an acquaintance, Davies, asking him to join in a yachting holiday in the Baltic Sea. Carruthers agrees, as his other plans for a holiday have fallen through, and because of a heartbreak due to a woman he courted becoming engaged to another man. He arrives to find that Davies has a small sailing boat (the vessel is named Dulcibella, a reference to Childers's own sister of that name), not the comfortable crewed yacht that he expected. However Carruthers agrees to go on the trip and joins Davies in Flensburg on the Baltic, whence they head for the Frisian Islands, off the coast of Germany. Carruthers has to learn quickly how to sail the small boat. Davies gradually reveals that he suspects that the Germans are undertaking something sinister in the German Frisian islands. This is based on his belief that he was nearly wrecked by a German yacht luring him into a shoal in rough weather during a previous trip...|Wikipedia|