Hooray! I've found the rest of the set of the American Heritage Guide to the States at Goodwill this evening.
I've been holding on to volume one since I acquired it as a kid, and the photos from the 60's mesmerized me then. Now Cookie Monster is infatuated with them.
I wondered if I would find them. Now Cm will be able to see how much this country has grown and sadly, how much industry isn't done here anymore. Best yet they were considered kids books so they were a buck apiece.