20th Century Boys is a mystery thriller manga series written and illustrated by Naoki Urasawa, and was published from 1999-2006, then in 2007 two more volumes were published after the conclusion of the original series to properly end the series, and was titled 21st Century Boys. Without getting into too many spoilers, the series is about a guy named Kenji Endo and his group of friends, who as kids create a "Book of Prophecy" about a story to save the world. Years later, on the cusp of the 21st century, the world is plunged into chaos as a mysterious cult leader known only as "Friend" begins to make the Book of Prophecy reality, and is set on destroying the world. Despite the popularity of the series, it currently has no anime adaptation.