I believe in Sherlock Holmes : early fan fiction from the very first fandom : includes Mark Twain, O. Henry & others

When Arthur Conan Doyle killed off his fictional sleuth in the 1893 story "The Final Problem," distraught readers resorted to producing their own versions of Sherlock Holmes's adventures{u2015}thus inventing the now-common genre of fan fiction. These tales by famous and lesser-known devotees offer the best of early Sherlockian tributes and parodies. Editor Douglas G. Greene's informative Introduction provides background on each of the stories and their authors. The collection begins with Robert Barr's "The Great Pegram Mystery," a satire that appeared less than a year after the very first Holmes short story. Thirteen additional tales include Bret Harte's "The Stolen Cigar Case," praised by Ellery Queen as "one of the most devastating parodies" ever written about the Baker Street investigator; Mark Twain's "A Double-Barrelled Detective Story," featuring Holmes's nephew, Fetlock Jones; and "The Sleuths," by O. Henry, in which a bumbling New York private eye struggles to outshine a rival