For tome owners who are on paid plans, there is the option to make tomes private. This means that the published version is not open to anyone to view, but instead only to registered users to whom you have given access.

Go to the tome's settings and set the 'visibility' dropdown.

You can invite members to a tome and set them as 'read-only' users for this purpose. They will not be able to make changes and can only view the published content.