I read a book set in a post-apocalyptic world who crossed the river to see what the audience knows are city ruins. He thinks they are filled with ghosts. I remember him going into an office building and sitting at a desk and I think there were pictures of a family on the desk. Does anyone know the name of this book?
"Daybreak 2250 AD" by Andre Norton?
This copy on Amazon has the same cover I remember: a guy on a raft going down a river, amid a ruined city: http://www.amazon.com/Daybreak-2250-A-D-Andre-Norton/dp/B000O8KU76
I read this back in junior high in the 60s - 'guess teens liking dystopian futures isn't unique to this new generation. :-)
Anyway, IIRC, the protagonist thinks the city is filled with ghosts, but it's really inhabited by what he calls "Beast Things" which are sort of like large, bipedal, sentient rats.
Now I'm wanting to dig up my ancient copy and read it again. Norton was a fantastic author.