I think the problem is that something other than just that alien book would survive from our society. I mean, if a book makes it, why not a few steel girders, a diamond ring, a few styrofoam cups??

Also would the tribe be able to repopulate the world and get the thing going again?

S & F, interesting thought.

I imagine a whole lot would depend on how long it took for the tribe to start spreading, and how thorough the destruction was. If enough time has passed, then our cities would have been reduced to rubble, girders corroded, concrete deteriorated. Books would mold or burn, CD's and other digital forms of information would be completely unreadable, if they survived at all.

I also imagine that if, somehow, some media could survive (books, magazines, whatever), the archaeologists of the future might assume that our celebrities were deities. They might conclude that sports teams were really names of tribes, and that there were endless wars between these smaller tribes, sometimes on a daily basis.

OTOH, they might not follow the course we've taken, but go in a completely different direction we can't even imagine right now. So much depends on whether (and when) they develop agriculture, medicine, taming of various animals, inventions (wheel, for example).