Billy's Past Becomes Jumbled To Himself

In the later half of the chapter, the author writes "That was I. That was me. That was the author of this book" (160). So we are left to believe that, like the first chapter had stated, "All this happened, more or less. The war parts, anyway..." (1). However, how much is actually true? The author keeps following Billy's crazy "timetravels", and it is getting more and more confusing. Is he just dreaming? But if he is, how does he know that Edgar Derby is going to die? Also, how does he keep going into the future, and then the past? Is he just imagining the future? Or is it all really going to happen in his life?

Suddenly, we are swung back into 1968, and his daughter Barbara was talking to him. She had just asked him if he heard what she had said. Perhaps, after surviving the plane crash, his brain had been slightly damaged. So, when remembering the past, he added bits and pieces, until he forgot what was real, and what was unreal. It may be, that when he was thinking of the past, certain memories were meshed with dreams and also the future.
Although he had not yet experienced certain things, or even known what was going to happen, this story may be being told by his knowledge of his life in 1968. Therefore, he had already experienced the death of Edgar Derby, and therefore believed that before Edgar Derby's death he had known what was going to occur. I found a blog which explains my theory quite well. Click here to read the blog.