According to o'brien he states that "The Things They Carried is in part a book about the Vietnam War. In part it's a book about the power of stories in our lives. In part it's a book about reimagining events and revisiting events thirty years or more after they've occurred. As I say each of these things it's a little bit like pulling a strand out of a piece of cloth, that in the end it's a book about all those things and the human heart as well."
An example can be found here: "In a true war story, if there's a moral at all, it's like the thread that makes the cloth. You can't tease it out. You can't extract the meaning without unraveling the deeper meaning. And in the end, really, there's nothing much to say about a true war story, except maybe “Oh.”