This is one of my frustrations with FTM 2012. I would like to create text document, etc that could be used in numerous books, and all books would be updated when the text document changed.
I go at it differently than Jamclo.
Background: First my principle books are based on each of my wife and my grandparents families. So there is minimal overlap.
For the maternal lines I end the report at the parents of the woman who marries in. ie grandparent john and eliz jones doe. Eliz family would end at her Jones parents family and extend back as far as I could push the family. This gives all of the uncles, aunts, and cousins at the generation the marriage occurred.
Rightly or wrongly I use the oldest person and create a descendants genealogical report. as it tends to limit the duplication if every genealogical report came to the present.
I start with the book, and added the modules that I want in the book. Each imported text document, report, and chart becomes an independent unit in the book. So while the data in the report will change as you update the database, the basic structure of the report is fixed once you import it into a book. ie you can change the structure of the independent report, but the book will retain the original version and not be affected by the update.
I do this because each genealogical report will be slightly different in each book. ie if family X marries into Family Y in the 3 generation it will be different from when Family X marries into Family Z in thee first generation.