ACE/Duplicate ISBN?

[Keith]

The current entry for ISBN 0850305519 published by Harper is linked here. I have another entirely different, earlier UK trade-paperback edition in hand with the same ISBN, but:
•published by The Aquarian Press ("part of the Thorsons Publishing Group")
•in 1987
•with a completely different cover

While I am a Superlibrarian myself, I am uncertain of the process for adding such a variant, as I've never encountered a case quite like this (both ACE and duplicate ISBN), and I want to ensure the linkages go in correctly. I could use some help from another Super here. Also, I am not seeing the ACE or ISBN tool links where I was expecting them, so I think something might have changed in the process while I was off doing other things.

Once the new edition has been added, I can attach a photo of the cover, which does not match any of the other existing editions.

Much thanks in advance.

[David]

It's actually simpler than it seems. The 1987 edition is an ACE of the 1999 edition.

The confusion arises because The Aquarian Press was part of the Thorsons Publishing Group, which was acquired by Harper Collins in 1989 (?). Now, it's under HarperNonFiction. As a result, when Harper reprinted a new edition, they used the old ISBN, which is appropriate.

To fix this, just add the 1987 edition as a new edition and add a librarian message to the 1987 edition: "ACE of ISBN 0850305519."

[Keith]

Thanks for your guidance, David. I've implemented the new edition as suggested; obliged if you'd care to check my work to ensure that I got it right.

[David]

It's perfect. I also added a librarian note to the newer edition.

[Keith]

Ah, yes, thank you kindly!