The Guns of August
I actually listened to the audiobook read by Naomi May, who was a great narrator. Unfortunately as interesting as the book subject was and as good as her narration was, I could not get into this book.
History was never my best subject (that would be math), but I do remember bits and pieces about WWI. Unfortunately the subject doesn't work for an audiobook. There were too many people whose names I didn't already know and I could never remember exactly who they were throughout the book. I may read this as a book one day since that will probably be easier to keep everyone straight.