A Case of Identity

This story was the basis for the third Holmes adventure (released in 1921) in the silent Stoll film series starring Eille Norwood.[4]

In 2001, this was the basis for the last episode of the animated television series Sherlock Holmes in the 22nd Century.[5]

In 2014, it is seen in "The Empty Hearse", from the BBC television series Sherlock, as one of the cases Sherlock works on with Molly Hooper assisting him. Mary Sutherland was portrayed by Elizabeth Coyle. Molly Hooper was portrayed by Louise Brealey.

In the fourth episode of the 2014 Japanese puppetry television series Sherlock Holmes, Mary Sutherland is a pupil of Beeton School. She is in love with the senior Hosmer Angel who suddenly disappears in a cave at the back of the school. Holmes, a pupil who lives in room 221B of Baker Dormitory, suspects that Angel and Windibank, one of the childhood friends of Sutherland, are the same person and he and Watson find out that there is no pupil called Hosmer Angel in the school. Holmes appreciates Watson for consoling the broken-hearted Sutherland. Watson tells Holmes, who criticises novels as in the original story, that he is wrong to do so because various things can be learned from novels including how to understand the female mind.[6]

Edith Meiser adapted the story as an episode of the radio series The Adventures of Sherlock Holmes, which aired on 5 May 1932, starring Richard Gordon as Sherlock Holmes and Leigh Lovell as Dr. Watson.[7] Another episode adapted from the story aired on 21 April 1935 (with Louis Hector as Holmes and Lovell as Watson).[8]

Edith Meiser also adapted the story for the radio series The New Adventures of Sherlock Holmes with Basil Rathbone as Holmes and Nigel Bruce as Watson. The episode aired on 30 November 1941.[9] Another adaptation of the story aired in the same series on 30 May 1948 (with John Stanley as Holmes and Alfred Shirley as Watson).[10]

John Gielgud played Sherlock Holmes and Ralph Richardson played Dr. Watson in a radio adaptation that aired on the BBC Light Programme on 2 November 1954. It was broadcast on NBC radio on 23 January 1955.[11]

A radio adaptation aired in 1969, as part of the 1952–1969 BBC radio series starring Carleton Hobbs as Holmes and Norman Shelley as Watson. It was adapted by Michael Hardwick.[12]

The story was adapted in 1990 by Peter Mackie as an episode of the 1989–1998 BBC radio series, starring Clive Merrison as Holmes and Michael Williams as Watson, and featuring Susannah Corbett as Mary Sutherland.[13]

A 2014 episode of the radio series The Classic Adventures of Sherlock Holmes was adapted from the story, with John Patrick Lowrie as Holmes and Lawrence Albert as Watson.[14]

Colin Dexter, known for writing the Inspector Morse novels, wrote a short story based on this called "A Case of Mis-Identity", in which Holmes's brother Mycroft is involved in the case's deduction; in this story, Holmes's theory about the 'Hosmer Angel' character is the same, while Mycroft deduces that 'Hosmer Angel' is a fiction created by the mother and daughter to eliminate the step-father, only for Watson to reveal that 'Hosmer Angel' is actually a real person who was attacked and robbed on the way to his wedding, hospitalized, and eventually treated by Watson, who used his own detective skills to verify the man's identity.[15]

The story was adapted as the beginning of the third case in the 2016 Frogwares video game Sherlock Holmes: The Devil's Daughter. Watson is not present when Mary Sutherland arrives and Sherlock is accompanied by Orson Wilde, an American actor training to play him. The player can come up with different conclusions to the case and also make a choice concerning telling her the results of his deduction.

Keith R. A. Decandido's short story, "Identity: An Adventure of Shirley Holmes and Jack Watson" updates the story to modern-day Manhattan. Here, the explanation is changed from nearsightedness to prosopagnosia, or face blindness.