Old Books

The other day I was driving along and I saw an old red barn with the words "Old Books" written in GIANT letters along the side. It made me curious as to what the barn might contain. Any ideas? My buddy Derek happened to be with me, and we queried this conundrum throughout our drive. With much debate, and many laughs, we could only assume that within that barn are some of the rarest, oldest, and best books mankind has ever not seen. Do you think this is correct? Or could we be wrong? O.O