The Adventure of Charles Augustus Milverton

Sir Arthur Conan Doyle was an 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.
In the story «The Adventure of Charles Augustus Milverton», Holmes is hired by the débutante Lady Eva Blackwell to retrieve compromising letters from a blackmailer: Charles Augustus Milverton, who causes Holmes more revulsion than any of the 50-odd murderers in his career. Milverton is "the king of blackmailers" and he makes his living out of blackmail. He demands £7,000 for the letters, which would cause a scandal. Holmes offers £2,000, all Lady Eva can pay, but Milverton insists on £7,000. It is worth £2,000 to him to make an example of Lady Eva. Holmes resolves to recover the letters by whatever means necessary...