Based on the 2010 book of the same name by Justin Cronin. The second book is called 'The Twelve' and the third is 'The City of Mirrors.'
The title of each episode is a line said by one of the characters.
In July 2007 Fox 2000 paid $1.75 million for the film rights to The Passage by Justin Cronin.[10] In September 2009 John Logan was announced to be writing a screenplay with Ridley Scott attached to direct. In April 2011 Matt Reeves was announced as director. In June 2011 Jason Keller was hired to rewrite Logan's screenplay. The producers decided that the project would work better as a television series and in November 2016 Fox gave a pilot production commitment. In January 2017 Fox ordered the pilot. In August 2017 Fox Entertainment president David Madden told Deadline that there would be potential re-shoots to the pilot. In February 2018 it was revealed that there would be re-shoots of the pilot, to take place in March in Atlanta. In May 2018 Fox ordered the pilot to series.
The book 'The Passage' by Justin Cronin is a 766 page behemoth weighing over 2lbs.