The manga is serialized in Dengeki Daioh and is written by Kazuma Kamachi and illustrated by Motoi Fukuyama.
The anime series is set in Academy City before and during the events of A Certain Magical Index, in which the plot focuses on Mikoto Misaka, an electromaster who is the third strongest esper in Academy City, along with her friends: Kuroko Shirai, a teleporter and Mikoto's roommate; Kazari Uiharu, Kuroko's partner in Judgment, the city's public safety committee; and Ruiko Saten, Kazari's friend and classmate.
Eight DVD compilations, each containing three episodes and a mini A Certain Magical Index novel written by Kazuma Kamachi and art by Haimura Kiyotaka which features Kaori Kanzaki as the protagonist, were released since February 7, 2010.
A five-minute bonus episode was included with the Official Visual Book of the show released on July 24, 2010.
[1] A second anime season, titled A Certain Scientific Railgun S, aired between April 12, 2013 and September 27, 2013 and was simulcast by Funimation, who released the series on DVD between July and August 2014.