ISBN
Enter the ISBN(s). The code is recorded as given on the document as 10 digits separated into 4 parts by hyphens).

When a multi-volume work has a different ISBN for each volume, enter each ISBN.

If the multi-volume has, in addition, been assigned an overall ISBN prefer the overall ISBN. You can also select the number from the authority browse list.

Example: 0-571-55559-2

For more information see the cataloguing manual under: Identifier