🚀 go-pugleaf

Don, just to clarify things, I think the way you are using the terms Chapter, Book, and Document is at odds with the way these terms are used in the FM manual. For example, referring to the files in a book as "books" or "book files" is confusing. In the context of FrameMaker, here's how I use these terms:

A manual (which you can hold in your hand) is a book.
A FrameMaker book file is a file with a .book filename extension, and it represents one entire book (one entire manual).

A FrameMaker book file contains a list of the FrameMaker document files that make up the book. A FrameMaker document file has a .fm filename extension, and it can be a single chapter, an appendix, or a generated file such as a table of contents. You can use the same document file (chapter file) in more than one book if you want.