The Pursuit of the House-Boat

This fantasy book brings various historical and fictional figures together. After the House-Boat was hijacked by Captain Kidd at the end of A House-Boat on the Styx, the various members of its club decided that in order to track it down, a detective would have to be called in. So they hired Sherlock Holmes, who, at the time of the book's publication, had indeed been declared dead by his creator.