What to do with a Standard Book Number?

[Sarah]

I have an edition of this book that has Standard Book Number 671784811 instead of an ISBN, probably because it was published around the time of the transition to ISBNs.

I found one source that says to convert Standard Book Numbers into ISBNs by adding 0. Is that correct? Or is it better to treat it like an edition that doesn't have an ISBN?

To further complicate matters, 0671784811 is apparently the ISBN for a completely different book:
https://www.goodreads.com/book/show/3...

[Lobstergirl]

Does your book match any of the covers already in the database? It's true that adding zero in front of that number makes it a valid ISBN, but it's also true that Worldcat says that ISBN belongs to the Iyanla Vanzant book. Is the publisher of your copy Simon & Schuster?

[Sarah]

My edition looks like this:
https://www.goodreads.com/book/show/2...
(...because I added it.)

I checked and re-checked the SBN about six times, and that's definitely it. It could have been a misprint in the actual book. Also, apparently it is unusual for an ISBN to be reused for an unrelated book, but not unheard of.

[Lobstergirl]

Pocket Books is/was a subsidiary of Simon & Schuster, so I guess they re-used the ISBN. BTW in your book entry (the description, not the ISBN field) you should change SBN to ISBN and add the zero. Because that's really what it is. 1974 is well past the introduction of ISBNs.