While Memorial Day is often more about hot sales and empty patriotism these days, the real purpose is to remember those who have fallen in service of our country. Though the holiday originated after the Civil War, the publishing industry has been awash in WWII books in recent years for the simple reason that the firsthand witnesses are quickly disappearing—there are still a couple hundred thousand veterans, but they’re in their 90s. There are only a few years of firsthand memories remaining.