I saw a local tv program last night about an exhibit at The Library Of Congress called Books That Shaped America. It was a long interesting explanation of why some books are on the list and why books are not. Here is a list of the books.
http://myloc.gov/Exhibitions/books-that-shaped-america/Pages/SlObjectList.aspx
Click on the link above and then click on the HTML version for best viewing.
Or just click on the link below to go directly to the HTML version.
http://myloc.gov/Exhibitions/books-that-shaped-america/Pages/objectlist.aspx