It's actually a horror movie, with Eli as the tool of an evil God.
Christianity and/or Jehovah did start the war. Afterward, people did their best to wipe out the poisonous meme, destroying all the copies they could get their hands on... but one last carrier of The Virus
managed to get through and start the infection all over again.
Eli has a Pip-Boy, or something similar.
- The Vaulttech Assisted Targeting System lets him pull of so many improbably badass moves while taking minimal damage. When he was brought before Carnegie and shot, he was out of Action Points. He most be below level twenty, because he didn't have Grim Reaper's Sprint.
Eli's "voice" that told him to go west was really a radio broadcast.
- He knows where the "safe place" is right away. It's possible that he was trying to make it relate to Solara, who obviously wouldn't know what a radio or Alcatraz is. He could have heard the radio broadcast and happened upon the Bible by chance while investigating it. Just in keeping with the apparent Fallout theme, the guy on the radio was Three Dog because he knows everything.
The men on Alcatraz are a benevolent Enclave.
- Instead of trying to genocide everyone in the wasteland, they're simply trying to preserve what they can find until they can make ground and begin teaching the wastelanders. Note that they look cleaner and seem more official than any normal wastelander (note the man who first points his rifle at Eli and Solara and the commands he shouts, and the other guards' uniforms).
- It could also be Brotherhood of Steel who dropped their militarism and picked up in interest in ruling the wastes and spreading knowledge. This is why they established an offshore base.
- It's probably the Followers of the Apocalypse.
The Flash is really what happened after the events of Unthinkable
- Either the three-to-four nuclear bombs were enough to to make America a barren wasteland, or that the bombs just increased the heat on the war.
Solara is the Dragon's daughter
- It explains why he wants Solara in exchange for finding Eli, why during the standoff he says 'please' to Eli, and why he looked so surprised when Solara indirectly kills him. This implies that he slept with Carnegie's concubine. Carnegie isn't the kind of man who would continue to employ the man who had cuckolded him, or continue a romantic relationship with the woman who had done so, either, so it must have been a secret relationship.
Eli is not actually blind
- Instead he's legally blind, only able to see short distances and make out basic shapes. This means that he can't see well enough to read a normal book, but he can see attacks coming and his spatial awareness is attuned to the point where it and his other senses are able to make up for his impaired vision.
- This explains why he doesn't see Alcatraz until Solara points it out on the sea.
- This explains why he jumps at the sight of the dead body in the room- he can tell it's a dead body.
- Alternatively, he has blindsight. That is, he can see, but he isn't consciously aware that he can see. It would explain how he can hit targets that are quite far away as well as why his eyes track movements nearby.
- That's their house... it's creepy. The windmill is the same too. Courage must have either died in the flash, or had died before.
The old couple had one Bible in their house
- They have a working phonograph, dishes, and all in all their house seems to have everything from before the Flash. Given how common Bibles are, it's likely they had the book Carnegie was looking for and in a format he could read. Dramatic Irony much? Given what they are, the irony increases. "This is my body/blood whenever you eat/drink it do this for the remembrance of me". The old folks just twisted it around a little.
The Book of Eli is loosely based on someone's play through of Fallout 3
- Maybe some details were changed, such as the reason why people were trying to kill Eli. Maybe they were mercenaries that were just given a story after Eli disabled the bomb in Megaton. The person simply has a mod that gave a bible to his character. Of course, the ending would be completely made up, possibly after the person had to drop their bible for some reason or another.
- Garry Whitta, the screenwriter of Book Of Eli, was the Editor in Chief of PC Gamer in the 90s. i wouldn't put it past him to have played Fallout 3.
- Note that there were two/three games (depending on how you count it) preceding Fallout 3, plus the original Wasteland— It seems likely that someone involved with the movie's look/atmosphere played one or more of said games, but considering that Eli began production a year before 3 was released it seems more likely that the movie was influenced by one of the older games.
It takes place before or during The Simplification. Either Alcatraz was eventually destroyed, or it managed to stay secret until after the first and second parts of A Canticle for Leibowitz
or there was another order bent on preserving knowledge.
- In Canticle the Church remained mostly untouched. Here it's eradicated with it's holy book.
Eli's iPod has an audiobook of the Bible.
Think about it: he committed the entire thing to memory and yet he was still zealously protective of the physical copy.
It's clear that he didn't want to take changes with the information being lost so he created another copy. Remember that he stopped in Carnegie's town for two things: water and recharging his ipod. Waiting for the second is why he was caught in another fight.
Solara is Carnegie's daughter.
Her mother is his concubine, after all, so he's by far the most likely candidate in the film. It could be that his lack of affection or care for her is meant to be a sign of his fundamental lack of humanity.
After the nuclear war, Guy Montag met up with all the other people who had memorized parts of the Bible
, and they entrusted Eli with remembering the whole thing.