Combining several documents into a master document
This method works best when all of the documents were created from the same template, but you can also use it when the documents were created from different templates.
Use one of the techniques described in
Starting with no existing documents to create a blank master document and insert the other documents as subdocuments of the master document.
This method is especially useful if the subdocuments are created or maintained by multiple writers. All writers on the project can work on their subdocuments without fear of version control issues that can occur when multiple people work on the same document.