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Second there's confusion about First Edition in that people collect First Editions and the phrase can mean a first printing of the original edition. Metadata is not trying track this – that a subset of a book's print run may or may not be collectible is not really a supply chain problem. If you are selling a proper collectible First Edition at a higher price and want it in the metadata, then that would be you'll need to issue a unique ISBN and it's metadata would provide an excellent use for the Edition Statement to add "Signed and numbered First Edition." It would likely only be available through direct order or at most a limited number of stores. All that can be accommodated in ONIX if necessary but generally we're talking about the books that retailers can buy and or sell for you – the regular run of the book – and the recommendations here are for representing regular book transactions.
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