I got this book because the letters were collected from Hoosiers, and as a Hoosier myself, I was interested.
The veterans (some of whose letters are published posthumously) are writing from the various battlefields of World War II, or during the occupation of Japan. Most harrowing are the accounts from Americans who entered the German concentration camps -- it is noteworthy that they often add words to the effect: tell everyone about this, at least if you think they could stand to hear it.
I have found that reading letters and memoirs written during or very shortly after a war are the most compelling. Often the writers can only see their own relatively small part in any engagement, while aware that something much larger is going on.
An account from legendary war correspondent Ernie Pyle is a great read; it was notable that some of the men writing from the Pacific theater named him, and mentioned being near Ie Shima where he was killed. War correspondents are not always appreciated, but Ernie Pyle was one who earned the respect of the men he encountered in Europe and the Pacific.
Other letters are clearly written for familiar friends and family and some are a bit boring. Over all, this is a fine collection, however, and provides a most interesting window into the experiences of "regular people" at the front, soldiers, some officers, nurses, and Red Cross personnel.