What do I need to know about ISBNs?

Do you need an ISBN? It depends. This chapter in our Indie Author's guide to Self-Publishing explains which bookstores require an ISBN, how to get one and other nuances. 

Each format of your book—ebook and PDF—will have a different ISBN. 

Here’s where to put those in your book in Pressbooks: 

• There is only one field for ISBN under Book Info. Here, we suggest you include your ebook ISBN if you have one. That way it will be included in your ebook’s metadata.  
• If you have an ISBN for your EPUB files, insert it in this field, then Export just the version it belongs to. Repeat this process for the other file formats which require a different ISBN. Note that you will need to create a custom copyright page in order for the ISBN to appear along with your other copyright information.
• When making your book covers, be sure to include your print book ISBN when making the print book cover. The cover generator will add it to the bar code on the back of your book cover.