Once a hot property in Hollywood, Allen and Albert Hughes need a strong success to reestablish their reputation as a directing team. It's been a long time since their last major collaboration, 2001's From Hell, and they are still smarting from its failure to catch on at the box office. As Allen wryly puts it in an interview with the Wall Street Journal:
One day you feel like Superman, the next you feel like you have a kryptonite suppository.
Because of this, the pair pushed hard for the chance to direct The Book of Eli, pitching it to studio executives with a 60-page manifesto illustrating their vision for the movie.
Despite the desperate need for a comeback, they have taken some serious risks with the movie, in particular by playing up the religious aspects of their post-apocalyptic western. Although they toned down the proselytizing in some early versions of the script, they vetted some pretty edgy promotional material, including a poster featuring the frontier town's head honcho, played by Gary Oldman, with message "Religion is Power."
Looking for a universal tone to balance out the mayhem of a post-apocalyptic world and reflect contemporary social angst, they felt that despite the risks, religion had to be a key element of the movie, although, as Allen explains, the particulars of the religion weren't that important:
People are looking for meaning. So you take the Bible and try to speak to all these yearnings in society right now. But it could have been the Torah or the Koran. The Bible is just more, for lack of a better term, commercial.