Pandemonium is a 2012 dystopian young adult romance novel written by Lauren Oliver and the second novel in her Delirium trilogy. The book was first published on February 28, 2012 through HarperTeen and follows the series' protagonist as she explores the Wilds outside the walled community she was raised in. The book was preceded by a novella entitled Hana and was succeeded by Requiem, the final book in the series. Source: Wikipedia (en)