20th Century Boys

20th Century Boys (20世紀少年, Nijusseiki Shōnen?) is a Japanese manga series written and illustrated by Naoki Urasawa. It was originally serialized in Big Comic Spirits from 1999 to 2006, with the 249 chapters published into 22 tankōbon volumes by Shogakukan. In January 2007, a "sequel" titled 21st Century Boys (21世紀少年, Nijūisseiki Shōnen?) ran until July for 16 chapters, which were gathered into 2 tankōban. It tells the story of Kenji Endō and his friends, who notice a cult-leader known only as "Friend" is out to destroy the world, and it has something to do with their childhood memories. The series makes many references to classic rock music, its title being taken from T.Rex's famous song "20th Century Boy", as well as a number of 1960s-1970s anime.

A trilogy of live-action film adaptations, directed by Yukihiko Tsutsumi, were released in 2008 and 2009. The manga was licensed for an English-language release by Viz Media in 2005; however, at Urasawa's request, it was rescheduled until after their translation of Monster finished. The films were also licensed by Viz in North America and by 4Digital Media in the United Kingdom.