The Voyages extraordinaires (; ) is a collection or sequence of novels and short stories by the French writer Jules Verne. Fifty-four of these novels were originally published between 1863 and 1905, during the author's lifetime, and eight additional novels were published posthumously. The posthumous novels were published under Jules Verne's name, but had been extensively altered or, in one case, completely written by his son Michel Verne. According to Verne's editor Pierre-Jules Hetzel, the goal of the Voyages was "to outline all the geographical, geological, physical, historical and astronomical knowledge amassed by modern science and to recount, in an entertaining and picturesque format ... the history of the universe." Verne's meticulous attention to detail and scientific trivia, coupled with his sense of wonder and exploration, form the backbone of the Voyages. Part of the reason for the broad appeal of his work was the sense that the reader could really learn knowledge of geology, biology, astronomy, paleontology, oceanography, history and the exotic locations and cultures of the world through the adventures of Verne's protagonists. This great wealth of information distinguished his works as "encyclopedic novels". The first of Verne's novels to carry the title Voyages Extraordinaires was The Adventures of Captain Hatteras, which was the third of all his novels. The works in this series are adventure stories, some with overt science fiction elements (e.g., Journey to the Center of the Earth) or elements of scientific romance (e.g., Twenty Thousand Leagues Under the Sea). Theme In a late interview, Verne affirmed that Hetzel's ambitious commission had become the running literary theme of his novel sequence: However, Verne made clear that his own object was more literary than scientific, saying "I do not in any way pose as a scientist" and explaining in another interview: Publication In the system developed by Hetzel for the Voyages Extraordinaires, each of Verne's novels was published successively in several different formats. This resulted in as many as four distinct editions of each text (labeled here according to current practice for Verne bibliographies): Éditions pré-originales (pre-original editions): Serialization in a periodical, usually Hetzel's own biweekly Magasin d'Éducation et de récréation ("Magazine of Education and Recreation", founded 1864). The serialized installments were illustrated by artists on Hetzel's staff, such as Édouard Riou, Léon Benett, and George Roux. Éditions originales (original editions): complete unillustrated texts published in book form at 18mo size. (Similar versions in the slightly