Exploring themes as diverse as spirituality, astronomy, science and depravity, Poe's writing is as powerful and arresting today as when he was first published. Poe's 6 years in Philadelphia, 1838-1844, were his most productive. Not only did Poe edit and provide critical reviews for very successful magazines, but he also invented the modern detective story. While in Philadelphia, Poe penned such classics as ''The Tell-Tale Heart,'' ''The Fall of the House of Usher,'' and poems like ''The Haunted Palace'' and ''To Helen.''