Who is Holmes? The world's most famous detective? A drug addict with a heart as cold as ice? A millstone around the neck of his creator? He's all of these things and much, much more.

Sherlock Holmes was the brainchild of Portsmouth GP Arthur Conan Doyle. A writer of historical romantic fiction, Doyle became unhappy that the detective's enormous success eclipsed his more serious offerings. But after attempting to wipe him out at the Reichenbach Falls in Switzerland, Doyle was faced with a vociferous backlash from the general public and eventually he had no choice but to bring his sleuth back from the grave to face more puzzling mysteries.

While not strictly speaking 'canonical', Holmes' deerstalker, curved pipe and cries of 'Elementary, my dear Watson!' have been immortalised in countless stage, film, television and radio productions. An iconic fictional creation, inseparable from his partner-in-crime Dr John Watson, Sherlock Holmes has charmed and fascinated millions of people around the world since his first appearance over a century ago. He is one of English literature's finest creations.

Mark Campbell on Conan Doyle's Dartmoor * Independent on Saturday *
Mark Campbell on Sherlock Holmes' London Haunts * Independent on Saturday *

MARK CAMPBELL has written for various publications, including Midweek, Girl About Town, The Bookseller, The Independent, The Dark Side and Infinity; he was one of the main contributors to the exhaustive two-volume encyclopaedia British Crime Writing in 2009. He has written Pocket Essentials about Doctor Who, Sherlock Holmes, Agatha Christie and Carry On Films. He was theatre critic for The Kentish Times for eight years. He lives near the river in Crayford, Kent and still hasn't got around to watching all those box sets.