Require a password
You can set a password so that only people who know the password can open an iBooks Author document.
Set a password
If the Document inspector isn’t open, click Inspector in the toolbar and click the Document Inspector button.
Click Document and select “Require password to open” at the bottom of the Document pane.
Enter the password twice (once in the Password field and again in the Verify field), enter a hint to help you remember the password, and click Set Password.
To change a password, click Change Password.