If you do not want a custom book detail field to be displayed when adding a new book, you can inactivate it or delete it. However you cannot delete a custom book detail field that has already been used to record book details.
To make fields inactive
Click Edit beside the custom detail field you want to edit, select the Inactive status, and then click the Update button. The Custom detail fields that are inactivated will be moved under the Inactive fields list.
To delete fields
At the top of your dashboard, click the module access icon > Academics > Library > Manage Book Additional Details to open the Add additional details page.
Click Delete beside the custom detail field you want to delete.