Job

OK we get to the end of the book and read that Job lives happily ever after. I'm left with a question that probably doesn't get answered because it's not important, but it has always bugged me. Here it is. I get how instead of responding to Job questions, God's presence gives Job a peace that passes understanding and it's life changing for Job. But in chapters 1-2 we the readers are given the behind the scenes look into the events in heaven that led up to Job's problems. So this is my question: Who wrote the book and how did they find out what went on in heaven? I think that Job must be the original author, if not the written account at least the oral account and God must have filled him in on the details even though this is not included at the end of the book. Has anyone ever heard this question addressed? I know that I can over think things and miss the main point.