Academy City, despite having 80% of its 2.3 million population being students, is more advanced than any other nation worldwide. Its residents possess a supernatural ability known as "espers," which are ranked from level zero to five. Touma Kamijou, a powerless level zero esper, has an unusual phenomenon called "Imagine Breaker" that cancels out any supernatural powers when his right hand comes in contact with them. Despite this, he considers himself unlucky due to the misfortunes that frequently befall him.
One day, Index Prohibitorum Librorum lands on Touma's balcony and explains that she is being hunted down by magicians. This leads Touma to discover a new world where magic exists. As he grapples with the problems arising from both the scientific and magical realms, how will he resolve them?
As a series, Toaru Majutsu no Index has appeared numerous times in the Kono Light Novel ga Sugoi! rankings under the best light novel category; 1st in 2011, 2nd in 2012/13, 3rd in 2014, 4th in 2015, 7th in 2016, 3rd in 2017, and 9th in 2019.The series has been published in English as A Certain Magical Index by Yen Press under the Yen On imprint since November 18, 2014.