On the bottom of the very first page of the NFPA 70 National Electrical Code, highlighted in gray shading you will see the following:
This 2008 edition includes the following usability features as aids to the user. Changes other than editorial are highlighted with gray shading within sections and with vertical ruling for large blocks of changed or new text and for new tables and changed or new figures. Where one or more complete paragraphs have been deleted, the deletion is indicated by a bullet ( . ) between the paragraphs that remain. The index now has dictionary-style headers with helpful identifiers at the top of every index page.
It tells you that something has been removed from the book in that spot, that was there in the last edition.