International Standard Book Numbers (ISBNs) and Universal Product Codes (UPCs) are distinctive codes used to identify a particular item. We use these codes and numbers to identify the exact item you wish to sell.

You will find the ISBN or the UPC on the packaging and/or back cover of your item. You will find the Amazon Standard Identification Numbers (ASIN) on the page where the same item is sold at Amazon.com.

ISBN
Do not include hyphens when entering these numbers. However, if the 10-digit ISBN ends with the letter X, be sure to include it.

UPC
When entering a UPC, be sure to include the smaller numbers on the left and right sides of the bar code.

Note: In many cases, Amazon.com carries only the latest version of a product. Older versions or editions may have different UPCs. As a result, you may be unable to find an item by UPC, even though a very similar item is listed at Amazon.com.

ASIN
Amazon Standard Identification Numbers (ASINs) are unique blocks of 10 letters and/or numbers that identify items. You can find the ASIN on the item's product information page at Amazon.com.