You may need to configure folder permissions for reviewer roles. The Folder Action Permissions affect the topics that review participants see in the Reviews table of contents pane.
Assign the folder permissions to users in the Author module's Folder Action Permissions screen.
Permission for Read Objects only allows users to see a review; they cannot expand the book contents while the review is in progress.
Permission for List Objects allows a user to see a review and expand the book contents. If you are initiating a review, you must have a minimum of List Objects so you can view a book in the Review form's Book List.