Fictitious private detective, created by the English writer Arthur Conan Doyle in A Study in Scarlet 1887 and recurring in novels and stories until 1914. Holmes's ability to make inferences from slight clues always astonishes the narrator, Dr Watson. The criminal mastermind against whom Holmes repeatedly pits his wits is Professor James Moriarty. Holmes is regularly portrayed at his home, 221b Baker Street, London, where he plays the violin and has bouts of determined action interspersed by lethargy and drug-taking. His characteristic pipe and deerstalker hat were the addition of an illustrator.