Indexes, Directories or Registries - How to Use Them

CCGS has many index books and they are not always described as an index in our catalog.  It is a bit disappointing to discover an ancestor name without further descriptive content.  What to do?  The 3 volume directory entitled The French Canadians 1600-1900, An Alphabetical Directory of the People, Places and Vital Dates is an amazing resource and by reading Chapter II - How to Use This Book you will discover a great overview to using this directory and indexes in general.
Thus searching an index reveals a potential name, this information is followed by other resource texts, typically listed by title, volume and page(s).  If our CCGS Library has the named title, it will be located on the appropriate shelf.  But likely the listed title is located elsewhere, which means the next step requires using great librarian detective skills possibly starting with an internet search.  In my French Canadian search, I discovered that a title I want to review is located at the GFO library (which I understand has an extensive French Canadian section).  Marcia