The U.S. Army Song Book, published in 1941 "by order of the Secretary of War"

This book belonged to my Dad who was a tailgunner, waistgunner, and bombardier in the U.S. Army Air Corps during WWII when the Air Force was a branch of the Army.  The table of contents is interesting: random folk and pop songs interspersed with some from the previous war (the WWII generation sang these as school children), and many others with a military and/or patriotic feel, including the official anthems of the different branches of the military (except for the Coast Guard).

There were 10,000 war-related songs published during the American Civil War and General Lee has been quoted as saying that "an army cannot win without good music."  Although the American output of war-related songs during WWII didn't come close to matching the Civil War's number, Lee's statement was apparently still held in high regard eight decades later when America joined the war on Fascism and this book was published by the U.S. government to promote singing among the servicemen.