A friend is looking for titles of "old" US History books (preferably pre-WWI or WWII). Digital offerings are fine. Do you know of any?
I have used this site in the past. http://www.heritage-history.com/www/heritage.php?Dir=civ&MenuItem=american I use it for a reference guide. And you can usually find most of these on google books in free pdf form, if they are in public domain.