Foul Play: Charles Reade

 A desert island romance framed by a story of crime and detection- with an intensely proper pair of Victorian castaways who call one another Mr Hazel and Miss Rolleston all through the time they spend alone together- and a weak-chinned villain who takes to his bed when challenged.  The story is completely preposterous but rendered believable by Reade's attention to detail. A huge amount of book-learning has gone into sailing the ships, giving the island its flora and fauna and unpicking the forgery on which the plot turns.  Conan Doyle was a fan of Reade's and when the mother and son detective combo turned up- he a tunnel-visioned expert in handwriting, she an expert in reading body-language- and a blunt-spoken, hawk-nosed  contriver of cunning plans- I went "M-hmmmmmm…."