"The Man with the Twisted Lip" is a Sherlock Holmes short story by Sir Arthur Conan Doyle, first published in The Strand Magazine in December 1891 and later collected in The Adventures of Sherlock Holmes. The narrative begins with Dr. Watson assisting a friend in locating her missing husband in an opium den, where he unexpectedly encounters Holmes in disguise. Holmes is investigating the mysterious disappearance of a respectable man named Neville St. Clair. As the case unfolds, it reveals an unusual and unexpected double life, testing Holmes's powers of observation and deduction.