The superhero Wolverine time travels and changes storylines. On Torchwood, there's a pill popped to alter memories of the past. The narrative technique of retroactive continuity seems rife lately, given all the world-building in comics. Andrew J. Friedenthal deems retroactive continuity, or -retconning, - as a force with many implications for how Americans view history and culture.

Friedenthal examines this phenomenon in a range of media, from its beginnings in comic books and now its widespread shift into television, film, and digital media. Retconning has reached its present...