Create custom collections in Books on Mac
You can create custom collections to organize items in your library. A custom collection can include books, audiobooks, and PDFs.
Create a custom collection
In the Books app
on your Mac, click New Collection in the sidebar.Type a name for your collection.
Add books and audiobooks to a custom collection
In the Books app
on your Mac, click All (or another collection) in the sidebar.Select one or more items, then drag them to any of the custom collections.
You can also click 
, choose Add to Collection, then choose a collection.
Rename a custom collection
In the Books app
on your Mac, Control-click a collection in the sidebar, choose Rename Collection, then enter a new name.
Delete a custom collection
In the Books app
on your Mac, Control-click a collection in the sidebar, then choose Delete Collection.
Deleting a collection doesn’t delete the books or audiobooks in the collection; they’re still in your library.