The plots are pleasingly preposterous and often quite lurid, some revisiting familiar tales from the canon, such as A Study in Scarlet or The Copper Beeches. Others tread new ground. The Bogus Laundry Affair takes the reader into the sinister underworld of London, while The Adventure of the Pharaoh’s Tablet, toys with the occult. The longest story and the final one in the book, For King and Country, starts in the First World War, with Watson at the Somme discovering a mysterious roomful of corpses neatly seated round a table. With more plot twists than a corkscrew, and a side trip to Turkey, the story ends in post-war France and a well-deserved retirement…