structural:summarization
Agents

Until Watson's arrival at Baker Street, Holmes largely worked alone, only occasionally employing agents from the city's underclass. These agents included a variety of informants, such as Langdale Pike, a "human book of reference upon all matters of social scandal", and Shinwell Johnson, who acted as Holmes's "agent in the huge criminal underworld of London". The best known of Holmes's agents are a group of street children he called "the Baker Street Irregulars ".