Goodreads also has something similar : https://www.goodreads.com/book/show/43056033-harry-potter

There is an explanation under "About the author" section :

This "author" was created to segregate those items which have ISBNs but are not actually books. For more information, see the manual and/or start a thread in the Librarians Group.

When an item which is not a book is imported via ISBN into Goodreads, it does no good to delete it: the item will only be re-imported as long as it remains on the feeder site. (Often these are book-related items which are assigned ISBNs by book publishers so that they can be tracked through their book systems.)

I wonder who the executive was who decided to start assigning International Standard Book Numbers to non-books.

“Why not? What’s the big deal?” said someone who has never worked with garbage data.

Not an executive, but a middle manager etc that said:

"paying $2-10k+ to add an International Standard Book Accessory Number field to their software will never get approved for a bookmark that works as a compass, or a promotional Harry Potter bookend set."

Tough to disagree.

Big booksellers whose whole systems are built around ISBNs as a primary key

When all you have is a hammer, everything looks like a nail.

"And hammer marks start to mysteriously appear everywhere."

"Not a bug, but a feature"

You buy ISBNs in blocks or individual numbers, and then submit whatever data you want.

There's very little control. E.g I just published a novel,and Amazon did not in any way validate that the ISBN I have them actually belonged to me - I had not yet registered the book data, so what I told them would not have matched anything they might have looked up.

In this case, based on the reviews on Amazon, it looks like someone changed the description of an existing product, and that the ISBN probably actually belongs to a book.

History section is clear:

ImportBot scrapes Amazon.com, matches product id with ISBN10 (which can be converted into ISBN13 without anything else IIRC), imports product as book.

Candle: https://www.amazon.com/gp/product/168298494X

> ISBN10 (which can be converted into ISBN13 without anything else IIRC)

Yes. There clearly only needs to be one way to identify things, so commonly larger systems just incorporate the smaller ones wholesale. The 13-digit system just incorporates the prior 10-digit system for International Standard Book Numbers with a 978 prefix called "bookland" (most prefixes in this system are geographic, but of course books aren't really from one single geographic region, so they're from "bookland") and adds a new set of possible codes. It also incorporates the entire 12-digit American "UPC" system.

Several other (less well known) systems were gobbled up the same way as "bookland", just allocating them imaginary geographic regions in the 13-digit system.

There's actually a fourteen digit system, but the lead digit tells you about how many of something are bundled e.g. so a distributor can distinguish a truck full of Pepsi cans from just one case or a single can in terms of things you can order. Lead digit 0 means "single" so if you know the 10 digit ISBN you can not only make a 13-digit EAN for that, you can make the 14-digit GTIN that means "just one of this book" which in most cases would be what you want.