Question: How many books are there in the series in which Aravis is a character?
Context: This page provides lists of best-selling individual books and book series to date and in any language. " "Best selling"" refers to the estimated number of copies sold of each book, rather than the number of books printed or currently owned.  Comics and textbooks are not included in this list.  The books are listed according to the highest sales estimate as reported in reliable, independent sources.  This list is incomplete because there are many books, such as "The Betrothed" by Alessandro Manzoni, "The Count of Monte Cristo" by Alexandre Dumas, or "A Christmas Carol" by Charles Dickens, that are commonly cited as "best-selling books" yet have no reliable sales figures because of the many public domain re-releases. During the run of the TV series "The X-Files", many books based on it were released, written, including novels based on episodes, a series of comic books from Topps Comics, and many "official" and "unauthorized" non-fiction books. Fr.  Bobby Jose Kattikad popularly known as 'Bobbyachan' or 'Fr.  Bobby Jose Capuchin' is a Roman Catholic priest from Order of Friars Minor Capuchin in India, known for his preaching and especially evangelization through television, radio and other media.  He founded Theo Publications in 2002, which publishes many books related to spirituality.  Fr.  Bobby is also author for many books which gained popularity around spirituality of malayalam speaking world.  The television preaching programs called Gurucharanam in Shalom TV India and many other programs are led by him.  Those programs are reported to have large number of viewers.  He also leads growth retreats which is conducted all over the world among Malayali communities.  For a long time, he was associated with conducting growth retreats in San Pio retreat centre, Kovilthottam, Kollam.  Fr.  Bobby was appointed as the first director and guardian of the retreat center.  He is an editor and contributor for a magazine called Theo Manushyasnehi. Arnold Roger Manvell (10 October 1909 – 30 November 1987) was the first director of the British Film Academy (a post he filled for over a decade), author of many books on films and film-making, and authored and co-authored (with Heinrich Fraenkel) many books on Nazi Germany, including biographies of Adolf Hitler, Rudolf Hess, Heinrich Himmler, Joseph Goebbels and Hermann Göring.  During World War II he worked in the Ministry of Information, creating propaganda films for the British government.  In his career, he also lectured in universities in as many as forty countries in three continents (America, Europe and the Middle East), and made a name as a broadcaster and screenwriter.  He joined the Boston University faculty in 1975 teaching film history classes at the College of Communications.  Manvell was named University Professor in 1982. Harriet Stratemeyer Adams (December 12, 1892 – March 27, 1982) was an American juvenile book packager, children's novelist, and publisher who was responsible for some 200 books over her literary career.  She wrote the plot outlines for many books in the Nancy Drew series, using characters invented by her father, Edward Stratemeyer.  Adams also oversaw other ghostwriters who wrote for these and many other series as a part of the Stratemeyer Syndicate, and rewrote many of the novels to update them starting in the late 1950s. Chris van Abkoude (6 November 1880, Rotterdam – 2 January 1960, Portland, Oregon) was a Dutch writer and novelist of mostly children's books.  He wrote the "series of Pietje Bell novels" from 1914 to 1936 and many books in between.  He moved to the United States in 1916 and wrote all the "Pietje Bell" books in the United States, except for the first one, which he wrote in 1914 in Rotterdam.  In 1923 Abkoude wrote the novel "Kruimeltje" ("Little Crumb") and in 1999 the film "Little Crumb" was released.  Before his writing career, Van Abkoude was a teacher; when he noticed the children did not like reading the children's books of the time, he wrote his own. Chelangatt Gopalakrishnan (June 6, 1932 - June 4, 2010) was born in Cherthala Alappuzha dist.  in Kerala to Sri Nediyedathu Kesava Pillai and Thrikkeparambil Ammukkutti Amma.  After graduation, he started his career as a journalist in a regional newspaper; Malayali.  Later he worked for some other newspapers including Mathrubhumi.  During this time, he established his own name in the film journalism.  Several forgotten personalities including J.C. Daniel, the father of Malayalam Cinema, have been disclosed before readers and public by him.  During this time he had released several books.  Most of them are about cinema and its history.  The historical narrations of cinema have been started from the birth of world cinema till the contemporary Malayalam films.  The renowned Malayalam Film Maker Adoor Gopalakrishnan in his book Cinemayude Lokam, which won many awards including the award from Government of India says ; "The history of Malayalam Cinema is not started with stars born with fortunes, from sky.  But, it is the tearful story of some, who experimented with their lives and assets.  Most of the experiments had been tragedies.  We got that history from the articles written by Chelangatt Gopalakrishnan.  S. Guptan Nair called Chelangatt Gopalakrishnan, the Chief Architect of Malayalam Film Literature and Journalism.  He was in the Kerala State Film Awards Jury for several years.  Many books related with novel, biographies, history and technical aspects of film making have been written by him.  He had run a film studio named 'Ajanta Studio' at Aluva.  Many classical films including 'Olavum Theeravum' written by M.T. Vasudevan Nair have been filimized at this studio.  He had written more than 20 books about cinema alone.  Vincent Muthal Vincent Vare, Mukhathodu Mukham, The History of World Cinema, The History of Indian Cinema, The History of Malayalam Cinema, The History of Film Persons in Kerala, The History of Malayalam Journalism etc., are few among them.  He was a regular writer about many of the prominent periodicals in Malayalam language. The Chronicles of Narnia is a series of seven fantasy novels by C. S. Lewis.  It is considered a classic of children's literature and is the author's best-known work, having sold over 100 million copies in 47 languages.  Written by Lewis, illustrated by Pauline Baynes, and originally published in London between 1950 and 1956, "The Chronicles of Narnia" has been adapted several times, complete or in part, for radio, television, the stage, and film. He is best known for his many books about the environment, national parks, and natural places, many of them in hundreds of libraries and by major publishers, including several titles in the series "The Earth's Wild Places" published by the Friends of the Earth in the 1970s.  His most widely read book, on Yosemite, is in over 1200 WorldCat libraries.  Many of his books have been published by the National Geographic Society.  Several of his books have been translated into Japanese, German, Spanish, and Hebrew.  He is the oldest son of the late environmentalist David R. Brower. Aravis is a fictional character in the children's fantasy series "The Chronicles of Narnia" by C. S. Lewis.  She is a main character in "The Horse and His Boy".
Answer: seven