The official U.S. Army history of World War II — the ubiquitous “Green Books” are now available in their entirety on the web through the U.S. Army's Center for Military History:  http://www.history.army.mil/html/bookshelves/collect/usaww2.htmlA fantastic resource for the student of US campaigns, usually only available through limited collections at research libraries or the odd copy at a used book store.