Introduction
‘You know my methods. Apply them, and it will be instructive to compare results.’ Arthur Conan Doyle, The Sign of Four (1890) ‘A Case of Identity’ (1891) opens, like so many stories in the Sherlock Holmes saga, in 221B Baker Street, where Holmes and Dr Watson receive a new client who bears a problem that is also a story. Watson is both Holmes’s pupil in the science of detection and, crucially, the story’s narrator. Both roles give him the scope to observe and record the client, Miss Mary Sutherland: his description for the reader of her ‘preposterous hat’, ‘vacuous face’ and ‘general air of being fairly well to do, in a vulgar, comfortable, easy-going way’ (...