A Certain Magical Index (とある魔術の禁書目録 (インデックス), Toaru Majutsu no Indekkusu) is a Japanese light novel series written by Kazuma Kamachi and illustrated by Kiyotaka Haimura, which has been published by ASCII Media Works under their Dengeki Bunko imprint since April 2004. The plot is set in a world where supernatural abilities exist. The light novels focus on Tōma Kamijō, a young high school student in Academy City who has an unusual ability, as he encounters an English nun named Index.