Amazon does not let sellers describe their own books. Every offer has to attach to a page that already exists in Amazon's catalogue, and the offer has to say which page. For most books the ISBN does that by itself. For a book with no ISBN there is nothing to match on, so the item never reaches Amazon at all until you tell it which catalogue page to use. That identifier is the ASIN.
What this means for your inventory
- Items with an ISBN match themselves. Nothing to do.
- Items without an ISBN will not list on Amazon until you give them an ASIN. Most pre-1970 books, ephemera, manuscripts, prints and privately printed material fall in here.
- Items whose ISBN matches more than one Amazon page, which happens with reprints and editions that share an ISBN, can attach to the wrong page or be rejected. Setting an exact ASIN pins them to the right one.
An ASIN also makes the ongoing sync more reliable, because BookRouter and Amazon are then talking about exactly the same catalogue entry instead of re-matching on an identifier each time.
Finding the right ASIN
Search Amazon for the book and open the product page for the edition and binding you actually have. The ASIN is in the page address, straight after /dp/:
amazon.com/Some-Book-Title/dp/0714842850/
It also appears in the Product details section of the page. For books the ASIN is very often the ISBN-10 itself, which looks wrong but is correct: use it as the ASIN.
Take care to match the right edition. An ASIN pins your offer to that exact page, so the wrong one puts your book on the wrong listing, which is a common cause of buyer complaints and returns.
Adding an ASIN to one item
- Open the item under Inventory › Manage Inventory and click Edit.
- In the tab strip, open the Marketplace Settings menu and choose Amazon.
- Scroll to Product Details. Set Type to ASIN and paste the code into Product ID.
- Save.
The item goes out to Amazon on the next routing run, attached to that catalogue page. This is the step worth building into your cataloguing routine for anything without an ISBN that you want on Amazon.
Adding ASINs in bulk
If a batch of your items is already listed on Amazon, from a previous service or from listing them there by hand, you do not have to look them up one at a time. Amazon will tell you every ASIN it holds for you:
- In Amazon Seller Central, go to Reports › Inventory Reports and run an Active Listings Report. It contains every SKU you have live, with its ASIN.
- In BookRouter, open Settings › Data Tools › Amazon Files and use Assign ASINs.
- Upload the report. The SKU and ASIN columns are found automatically. You can also paste pairs by hand, one per line, as SKU, ASIN.
- Leave Overwrite unticked to fill in only the items that have no ASIN yet, or tick it to replace existing ones.
You are told how many items were linked, how many already had an ASIN, and which SKUs from the report could not be found in your inventory.
SKUs in the report that we do not have
Those are listings on Amazon with no matching item in BookRouter, usually leftovers from an older system or from items sold long ago. BookRouter never touches a listing it does not know about, so they will sit on Amazon indefinitely. Check them in Seller Central and remove the ones that should no longer be for sale.
What BookRouter will not do
It never creates new Amazon catalogue pages. BookRouter adds your offer to pages Amazon already has. If your copy is genuinely not in Amazon's catalogue then no ASIN exists to link to, and the only way onto Amazon is to create the product once yourself in Seller Central under Catalogue › Add Products. After that it has an ASIN like any other page, and BookRouter maintains your offer on it from then on.
Items with no ISBN and no ASIN are simply skipped. They stay listed everywhere else you route to; it is only Amazon that needs the identifier.
Selling on an international Amazon site instead? Those are handled with upload files rather than managed routing, and the same ASINs apply. See the Amazon Files articles.