"The Leak" by Jacques Futrelle is a crime fiction novel written in the early 20th century. The story revolves around the fascinating exploration of a financial leak that leads to substantial monetary losses for a prominent financier, J. Morgan Grayson. Central to the narrative is Professor Augustus S. F. X. Van Dusen, also known as The Thinking Machine, who employs his scientific reasoning and deductive skills to uncover the truth behind the leak. The plot unfolds as Grayson seeks The Thinking Machine's assistance after suffering significant losses due to a mysterious leak of confidential information regarding his business dealings. He confesses that only he and his trusted stenographer, Miss Evelyn Winthrop, are privy to the sensitive plans he develops, yet they repeatedly become known to his competition. As The Thinking Machine investigates the situation, he deduces that Miss Winthrop has been cleverly using her skills as both a typist and a telegraph operator to communicate Grayson's plans to others unknowingly. This revelation culminates in a dramatic confrontation where the implications of trust, betrayal, and cleverness in the world of financial dealings create a compelling and thought-provoking narrative. (This is an automatically generated summary.)