Explain what you would do in this situation

You are an editor for a publishing firm. Your best fiction writer is three months behind in submitting the chapters on his next book. He assures you that they will arrive any day, however, you have heard this for the last three months and you are doubtful. It is important that the book be completed in the next month because it needs to be on the shelves for the Christmas season- the largest time of the year for book sales