The Bangor Maine Public Library has a great site with TONS of Unit History books from WW2 available in PDF form for download.
I just came across this today and successfully downloaded the "The Cross of Lorraine: A Combat History of the 79th Infantry Division, June 1942 - December 1945."
Many of these books were published after the war and were available to the Veteran's.
Included in many of these books are Unit Rosters, which are helpful in researching individuals and confirming service in a given unit. The 79th ID book I downloaded also includes those who received awards, Bronze Star, etc.
World War Regimental Histories | World War Collections | Bangor Public Library