Toshokan Sensou (書館戦争, lit. "Library War") is a Japanese light novel series by Hiro Arikawa, with illustrations by Sukumo Adabana. There are four novels in the series, though only the first novel is called Toshokan Sensō; the subsequent novels are named Toshokan Nairan, Toshokan Kiki, and Toshokan Kakumei. The novels were published by MediaWorks between February 2006 and November 2007. Two volumes of a spin-off series entitled Bessatsu Toshokan Sensō (別冊 図書館戦争?, lit. "Supplement: Library War") have also been published by ASCII Media Works. As of April 2008, the original four novels and volume one of the spin-off series have sold over 1.25 million copies in Japan. The story was inspired from the Statement on Intellectual Freedom in Libraries of the Japan Library Association.
A manga adaptation by Kiiro Yumi started serialization in the shōjo manga magazine LaLa on September 24, 2007 published by Hakusensha; another manga adaptation by Yayoi Furudori started serialization in the shōnen manga magazine Dengeki Daioh on November 21, 2007 published by ASCII Media Works. A twelve-episode anime adaptation by Production I.G aired on Fuji TV's Noitamina programming block between April and June 2008. Two Internet radio shows started in April 2008 meant to promote the series which are hosted by voice actors of the anime. An anime film produced by Production I.G was released on June 16, 2012. A live action film was released on April 27, 2013.
Toshokan Sensou tells the story of Kasahara Iku, the first woman to join the Library Task Force. In the near future in Japan, the Media Enhancement Law has been forced upon the population censoring all books and media. To counter this, the Library Defense Force was created. To protect themselves against the Media Enhancement Law Commission, all major libraries are fully equipped with a military Task Force, who take it upon themselves to protect the books and freedom of media of the people. This anime follows Iku and her fellow soldiers as they protect various special books and artifacts from the oppression of the Media Enhancement Law Commission. A love story, war story, and comedy all rolled into one.