The Harry Potter Compendium is a fan-created online website, an encyclopedia of the Harry Potter series. The Harry Potter Lexicon, also known as HPL, was created by school librarian Steve Vander Ark. It contains detailed information for all seven published Harry Potter books. The Compendium lists characters, places, creatures, spells, potions and magical devices, as well as analysing magical theory and other details of the series.The Compendium is credited as creating one of the first timelines of all events occurring in the Harry Potter universe. A similar timeline of events was adopted by Warner Bros. for inclusion with their Harry Potter film DVDs, and was accepted by author J. K. Rowling as conforming to her wors.