FitzJames O'Brien was an Irish-American writer born in 1828 in Dublin, Ireland. He is best known for his contributions to the genre of speculative fiction and is often considered a precursor to later science fiction writers. O'Brien's works include short stories that explore themes of the supernatural and the fantastic, showcasing his imaginative storytelling. O'Brien emigrated to the United States in the 1850s, where he became involved in the literary scene of New York City. His notable stories, such as "The Diamond Lens" and "What Was It? A Mystery," reflect his innovative ideas and unique style. He died in 1862 during the American Civil War.