23 is a 1998 German drama thriller film about a young hacker Karl Koch, who died on 23 May 1989, a presumed suicide. It was directed by Hans-Christian Schmid, who also participated in screenwriting. The title derives from the protagonist's obsession with the number 23, a phenomenon often described as apophenia. Although the film was well received by critics and audiences, its accuracy has been vocally disputed by some witnesses to the real-life events on which it was based. Schmid subsequently co-authored a book that tells the story of the making of 23 and also details the differences between the movie and the actual events.