If you don't own a copy of this book, you should get one. If your genealogical database is anything like mine, it contains lots of scraps of information collected over time. Genealogy is certainly not a linear science. Information often arrives in pieces and out of sequence. Our ability to personally verify each piece of information is limited to the time we have available, our access to locations and materials, and a variety of other factors.
Some people like to keep their databases pristine, entering data only when it has been verified.
I am a member of the alternate camp, entering data as I receive it and trying to annotate it with sources and comments about what it needs. I am now doing a better job of this than I was a few years ago. Today, verified facts have source citations in a standard format, and unverified facts are notated. Marriage date is listed as 26 December 1875 in book Jones, Robert. Printer Name. 1952.