reference to caps worn by some detectives, such as Sherlock Holmes, the best known of all fictional detectives, created by English author SirArthur Conan Doyle (1859–1930). Holmes's extraordinary powers of memory, observation and deduction enable him to solve mysteries and identify criminals in cases that leave all other detectives baffled. Holmes usually wears a double-billcap and a long cape, smokes a meerschaumpipe and carries a magnifying glass. His companion is Dr. Watson, who records his exploits. —NVRD Approved Glossary