The Baker Street Irregulars is a gang of young street children whom Sherlock Holmes often employs to aid his cases. They first appeared in Conan Doyle's first novel, A Study in Scarlet. They also appear in The Sign of the Four, one of the chapters from the novel is titled "The Baker Street Irregulars". The head of the group is called Wiggins. Holmes pays them a shilling a day (plus expenses), with a guinea prize (worth one pound and one shilling) for a vital clue.