Got posted a link about these,
The Center of Military History is very proud to offer for electronic download all the volumes of the U.S. Army in World War II “Green Books” collection. This seventy-nine volume series is widely recognized as the definitive study of the U.S. Army’s involvement in World War II. All volumes are available in PDF format and some in HTML. To access these books please follow the link below.
http://www.history.army.mil/html/bookshelves/collect/usaww2.html
Quite a selection of US Military books there available for download or to read online (Download as PDF or HTML). Some of it is quite interesting for an American point of view.