While actual fact is not copyrightable, everything in a book that supports facts are. Because of this, if a new book of genealogy is produced, it is able to state that Uncle Harry was born on his birthday, whether that fact was previously published in copyrighted work or not. As long as the author has done their own research and arrive at the same fact, it may be used.
What it does not cover is wholesale reuse of facts as previously published. Standard examples of copyright abuse involving facts can include (but not limited to):
- Adding photocopies of someone else’s data forms.
- Transcribing facts from a book without permission or research.