Depending on the size of the book, including how many chapter files and referenced images there are? Are all the book/chapter files in the same directory? Are all the graphics in a single directory?
- Create your new directory
- Copy the FM files to the new directory
- Open the book file. Do NOT open the chapter files
- Use the book file to rename the chapter files as needed. This will update all your xrefs and the TOC pointers for you.
After that it depends on the size of the book, how many images you have, and whether the images are located in one directory or scattered.
For a book with all the graphics stored in the same directory, I'd open the chapters and update to the new directory path since you only have to do it once per chapter file. This can get a little wearing if you have dozens of chapter files, but for anything with about 20 or fewer chapters the BFMI method is often the simplest and fastest method.
For a book with more than about 20 chapter files and/or with graphics located in multiple directories, I'd suggest looking into purchashing Rick Quatro's PathChanger utility, which writes the current directory locations out to an Excel spreadsheet where you can update the path manually and then write it back to the book.