how to delete books.

Read books and more with Apple Books - Apple Support explains:

"How to delete books, audiobooks, or PDFs from your Mac

1. Click Library at the top of the window, then click All Books in the sidebar.
2. Control-click or right-click the item.
3. If the item is part of a series, first open the series, then control-click or right-click the book.
4. Choose Delete.
5. When prompted, choose Delete from the window that appears.

If you don't see Delete after you right-click or control-click an item, that item isn't downloaded to your device."

You are welcome.