"Masterpieces of Mystery in Four Volumes: Riddle Stories" by Joseph Lewis French is a collection of mystery short stories edited in the early 20th century. This compilation aims to showcase the art of the riddle story, a subgenre intertwining elements of mystery and human psychology, while allowing readers to engage their intellect. The stories included represent a broad palette of authors and styles, hinting at a rich exploration of the people and situations that create mysterious conundrums. The opening portion introduces the first story, "The Mysterious Card" by Cleveland Moffett, which follows Richard Burwell, an American in Paris who receives a mysterious card from an enigmatic woman. His attempt to understand the card's cryptic message leads him into a whirlwind of strange occurrences, including evictions from hotels and a mysterious detention by police. The narrative quickly escalates as Burwell's quest for the card's meaning impacts his personal and social life, leading to suspicion and dire consequences that unravel his former stability. As the tension of the story unfolds, the reader is drawn into a spell of intrigue revolving around miscommunication, societal norms, and the search for hidden truths. (This is an automatically generated summary.)