I take a file folder on my MacBook Pro and put all the chapters of a book in progress into it. I keep them in order by beginning the title of each chapter with a number, like so:
That way the computer automatically keeps them in order. (I use 000 for the title page, table of contents, etc... so that chatper one can always be 001.) I can look at the ordered list and see the last time I worked on each chapter. The chapters switch order on me, as sometimes happens? I can rename the documents. Other documents in the folder that aren't actual chapters--article versions of parts of the book, for example--will not get numbers: the computer will list them afterwards so they won't clutter the list.