"The Adventure of the Speckled Band" is one of the 56 short Sherlock Holmes stories written by Scottish author Sir Arthur Conan Doyle. It is the eighth of the twelve stories collected in The Adventures of Sherlock Holmes. Helen Stoner worries her stepfather may be trying to kill her after he contrives to move her to the bedroom where her sister had died two years earlier, shortly before her wedding. Stoner is herself now engaged, and Holmes learns that her stepfather's annuity (from the estate of his wife—​​Stoner's mother) would be greatly reduced if either sister married. During a late-night investigation of the bedroom, Holmes and Watson discover a dummy bell-pull near a ventilator. As they lie in wait a whistle sounds, then a snake appears through the ventilator. Holmes attacks the snake with his riding crop; it retreats to the next room, where it attacks and kills Stoner's stepfather.

Sir Arthur Ignatius Conan Doyle (May 22, 1859 – July 7, 1930) was a British author most noted for his stories about the detective Sherlock Holmes, which are generally considered a major innovation in the field of crime fiction, and for the adventures of Professor Challenger. He was a prolific writer whose other works include science fiction stories, historical novels, plays and romances, poetry, and non-fiction.